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How to Optimize Images for Your Mobile Emails

Emily Santos
Emily Santos
Jul 1, 2016
How to Optimize Images for Your Mobile Emails
How to Optimize Images for Your Mobile Emails

Originally published on June 30, 2016. Last updated July 30, 2021.The rate of email opens on mobile is consistently increasing, with almost half of all emails opened on smart phones in 2021.

Responsive mobile emails compared to other devices

As webmail and desktop environments become less popular, it’s important for marketers and designers alike to keep up with best practices for mobile design. Factors like accessibility, image size, quality, and format not only affect how the design renders, but also impact important email marketing metrics like deliverability and conversion rates.If you’re new to optimizing for mobile design, you might be wondering: why do images in emails sometimes look pixelated on smartphones? What's the best size for an image in email? Why does my email show up differently depending on the ESP of the user?Let’s answer each question by running through best practices for mobile email image optimization. Add these tips to your design toolbox for future email campaigns.

Best practices for mobile design 

In order to create the best user experience, it’s essential to implement responsive email images for mobile. Smaller screens on mobile call for more accomodating design components, which could be intimidating or confusing at first. But keep in mind that optimizing for mobile should be user focused. Consider your users needs and then bring these best practices into every email you design.

Choose the highest quality photo

High-quality images are one of the most important aspects of image optimization. To ensure your images are showing up correctly in your email, you first need to evaluate their quality.Expert designers use DPI or dots per inch to measure the quality of an image. For guaranteed high-quality images, set your resolution to 72 DPI while also increasing the dimensions of the image. This will give high-DPI displays, which have increased pixel densities and more image data to utilize. This means that setting the DPI to this optimal resolution gives enough space for images to appear crisp.Implementing these changes will prevent blurriness and assure that your images are always looking sharp. When you don’t account for high-DPI displays your image will appear pixelated as it stretches across the screen. This means that you will typically want images to be twice as large for the best image optimization.It’s also important to think about your image’s color values. Avoid CMYK (cyan, magenta, yellow & black (key)) color values since they are solely meant for print and won’t work well on a digital screen. Keep images in RGB (red, green, blue) color values, which allows you to adjust for saturation and vibrancy. This is the best way to create the highest quality image.

Optimize image size

Always consider the dimensions of your images when inputting them into your emails. If images have larger-than-normal dimensions, they may not render well. It’s concerning and makes you question if subscribers will have issues upon opening the email and viewing the images?In short, the file size does play a role when the images are downloaded. The image size impacts the total time it takes for the content of the email to fully render once it's opened. On a mobile device, when the reader might have a slow Internet connection speed, the time lag could be substantial.Avoid this issue by optimizing your image size. We recommend adjusting your content area width to around 600px for the highest quality image. While images will adjust according to the device the email is open on, hit this size to make sure they render correctly on all devices. Leaving the size to chance will lead rendering to chance, especially with so many different file formats as well.

Select the best image format

There are so many file formats, it is often confusing to figure out which one will result in the highest quality images. PNGs, JPEGs and SVGs tend to be the most well-known and widely accepted file formats.While there are pros and cons to each format, you can use the guidelines below to choose the right file type for your needs. Also note, some formats may increase your image size, so use the EZGIF program to compress your image to keep in line with the quality you have adjusted for. So, which image format is best:

  • PNG: These are lossless, meaning they won’t falter in quality when you compress the image which allows you to export with transparency. There are PNG-8, 24, and 32 files, so the standard practice here would be to decide on a proper balance of file size and color to suit your email best.
  • JPEG: These won’t allow transparency and are quite lossy. Use when your images are loaded with color.
  • SVG: These are a vector format which allows you to resize your image to fit your needs without losing the quality of your image. 

There is no correct answer as to which format is best, but think about which one would fit your needs. If you are looking for something to easily export with transparency go with PNG format. Or use JPEG when you are using images with tons of color. Utilize the format that will give you the highest quality image.

Make your images accessible

The quality, size and file format of your images are set for success, but you have one last crucial factor to consider: Is your email accessible to everyone?Visually impaired individuals will not be able to decipher image-heavy emails that aren’t intentionally made accessible. It’s important to include accessibility concerns to avoid isolating users with disabilities.The two accessibility components that you shouldn’t go without are Alt text and color contrast.

  • Alt Text. This Alternative Text attribute is an image description that gives those using screen readers the opportunity to visualize what your picture is portraying. Consider what purpose your image serves inside your email to allow for proper alt text functioning
  • Color Contrast. Be mindful of your color choices in regards to your images and other email components. Distinguishing between colors is difficult for many, so try to increase the contrast between the email text, image and background. Refer to this color oracle for more on this. Especially think about this when trying to utilize background images, since older emails like Outlook don’t render those. If you choose to use a background image be sure to set a safe fallback color. 

Also be mindful of flashing graphics, color patterns or other special effects that may be dangerous to some image-sensitive subscribers. Seizures can be caused by bright, strobing images, so make sure to avoid those at all costs. Be sure to account for these image accessibility factors along with other email design elements including copy spacing, font size and other design elements.

Mobile Design Mode

We’ve gone through all of the best practices for optimizing your mobile design, including:

  1. Choose the highest quality photo
  2. Optimize size
  3. Select the best image format
  4. Make your images accessible

But the best way to make sure that your emails render correctly every time is to use the right tools. BEE Pro includes a mobile design mode, where you can design for mobile-only communications. Visualize exactly what your design will look like on a mobile device while you are designing.Sign up for a BEE Pro free trial to test this out, and access more templates and features to make designing with these best practices in mind even easier.Save

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What Are Email Security Gateways? A Guide to Secure Communications

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Getting Started with Beefree: A Guide to Streamlined Email and Landing Page Creation

Whether you're designing a newsletter, promoting an event, or driving a marketing campaign, ensuring that your emails and landing pages are visually appealing, engaging, and efficient to produce is no small task. That’s where Beefree comes in.
Beefree team
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Using Beefree with Marketo Engage 101

Learn how integrating Beefree with Marketo Engage can help you build high-converting, on-brand email campaigns— faster.
Luca Penati
Luca Penati
4 Apr
2025

Marketo Engage is a powerful tool for marketing automation, but when it comes to email design flexibility, many users find its built-in editor limiting. Creating visually compelling, mobile-responsive emails often requires custom coding or workarounds, slowing down workflow and making it harder to execute high-quality campaigns efficiently.

That is where Beefree comes in. By integrating Beefree’s no-code, drag-and-drop email design platform with Marketo Engage’s advanced automation capabilities, teams can build professional, responsive emails without coding headaches and push them directly to Marketo in just a few clicks.

This article explores:

  • The challenges of designing emails directly in Marketo
  • How Beefree solves these pain points
  • A step-by-step guide to integrating Beefree with Marketo Engage
  • Common FAQs and troubleshooting tips

The challenges of designing emails directly in Marketo

Marketo’s built-in email editor is useful for basic templates but presents several limitations for marketers and designers.

  • Limited design flexibility – Customizing layouts, fonts, or interactive elements can be difficult without custom HTML or Marketo’s proprietary syntax.
  • Technical barriers – Advanced customizations often require HTML knowledge or an understanding of Marketo’s email template language, which may not be ideal for non-technical teams.
  • Time-consuming manual processes – Without a centralized style kit, teams may struggle to stay on-brand and often have to manually recreate headers, footers, and other reusable content blocks for each email, adding extra steps and slowing down production.

Due to these challenges, many marketing teams turn to external email builders like Beefree, FeedOtter, or Knak to improve design efficiency and automation.

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Why Beefree is the best email builder for Marketo Engage

While other external email builders like Knak and FeedOtter also integrate with Marketo, Beefree offers distinct advantages.

  • No-code drag-and-drop builder – Enables teams to design professional emails without writing any code.
  • Advanced design features – Provides more customization options beyond what Marketo’s built-in editor allows.
  • Mobile-responsive templates – Ensures emails adjust automatically for both desktop and mobile devices.
  • One-click export to Marketo – Simplifies the process of moving email designs directly into Marketo Engage.
  • Ability to update existing templates – Allows quick updates without requiring manual re-imports of HTML files.
  • Team collaboration – Enables teams to work together in real time, with built-in guardrails and approval controls to ensure error-free emails before exporting.

By integrating Beefree with Marketo, marketing teams eliminate design frustrations and manual email imports, allowing them to focus on high-performing email campaigns.

Learn more about Beefree's integration with Marketo Enagage [https://support.beefree.io/hc/en-us/articles/24837761625618-Export-Emails-to-Marketo]

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How to update existing email templates in Marketo

Instead of manually editing HTML, Beefree allows users to edit emails in Beefree and update existing ones in Marketo Engage with one click.

  1. Open the email design in Beefree.
  2. Make changes and click “Export.”
  3. Select “Update Existing” to overwrite the previous version in Marketo Engage.

This feature ensures that emails and templates remain up to date without requiring complex HTML edits or duplicates.

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Frequently asked questions on using Beefree with Marketo Engage

Can I use Beefree with other ESPs besides Marketo Engage?

Yes! You can connect Beefree to any ESP, MAP, or CRM including Mailchimp, HubSpot, Salesforce Marketing Cloud, and others. To learn more about how to integrate Beefree to your sending platform watch the video below: 

For a full list of our native integrations visit [https://beefree.io/integrations].

Are there any limitations when exporting Beefree emails to Marketo?

Yes, there are a few important limitations to be aware of:

  • Charset emojis are not supported in Marketo. Including emojis in your email content may result in an error. To prevent this, Beefree automatically replaces unsupported emojis with a placeholder. For more details, refer to the [Marketo documentation on emoji support].

Preheader text is not a native field in Marketo. However, Beefree includes it by embedding the preheader directly in the email's HTML code during export.

Additional resources and links

Why you should use Beefree with Marketo Engage

By integrating Beefree with Marketo Engage, marketing teams gain a faster, more flexible way to build high-converting, on-brand email campaigns—while leveraging Marketo’s powerful automation and analytics to track performance and optimize results.

  • Design responsive, professional emails with ease.
  • Maintain brand consistency across every message.
  • Collaborate efficiently and gain insights to improve campaign performance.

Ready to elevate your Marketo email marketing? Try Beefree today and streamline your entire email creation process.

Start your 15-day free Business trial today!

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What Are Email Security Gateways? A Guide to Secure Communications

Are your newsletters being marked as spam? Discover all you need to know about email security gateways and how to create emails that pass all the checks.
Beefree team
Beefree team
12 Mar
2025

Email is king when it comes to talking directly to your customers. Sure, we might send texts or share voice notes, but we all still check our emails. It’s how we keep in touch with work and the businesses we connect with. 

As an email marketer, this puts you in prime position to get your business’s brand right into the hands of your customers. The problem, however, is that you must first get past the metaphorical guard dog known as the secure email gateway (SEG). 

SEGs use sophisticated methods to identify and block spam and phishing emails from ever entering a person’s inbox. While your email newsletters should go through, that doesn’t necessarily mean they will. That’s why businesses need to know what a secure email gateway is and how it works. Know this key info, and you’ll be able to improve the chances of your emails reaching their destination. 

What are email security gateways? 

Protecting yourself from cyber threats is the basis of all cybersecurity risk assessment services. One of the biggest gaps in any security armor is phishing emails. If they get through and someone clicks a link they shouldn’t have, it’s almost impossible to stop the damage. 

The victim could be anyone. The link could lead to a ransomware virus that holds your data captive or be the start of a data breach. It could even lead to a traditional scam that has you input your credit card details so a thief can steal them. 

For all these reasons and more, email providers consistently invest in security features to help protect their customers. One such feature is an email security gateway. 

A secure email gateway uses AI and machine learning to screen incoming emails, identify spam, and stop it from entering. If there’s any doubt, the system quarantines the email in your spam box for review. 

Why are secure email gateways important?

While we are getting better at filtering out spam emails, an estimated 45.6% of emails sent in 2023 were still spam. This poses a massive security risk for consumers, businesses, and governments alike. 

According to IBM, businesses are hit the hardest, with the global average cost of each successful phishing attack increasing to $4.88M USD. The attacks don’t just hit businesses, either, with attacks targeting individuals and even charities.

Just as phishing and spam emails have become more sophisticated, so have the tools designed to protect against them. All providers, including big names like Gmail, use SEGs to secure communications and other features, such as Gmail’s unsubscribe feature

What do SEGs flag as spam? 

SEGs continually update their parameters. This means that what they check for is constantly in flux. What SEGs look for today, for example, could include: 

  • Strange or suspicious subject lines
  • Highly urgent capitalization or excessive exclamation points
  • Strange URLs
  • Poor grammar and/or spelling
  • Generic greetings that don’t address the recipient 
  • Suspicious email addresses
  • The volume of emails sent at once
  • Attachment types 
  • Image-heavy content 

SEGs are far more advanced than just ticking boxes, but that doesn’t mean your emails can’t get blocked or sent to spam. After all, you might put together a great email campaign, but if your email is too image-heavy, it might get quarantined or sent to spam. 

The good news is that once you know what the SEGs look for, you can work to design better emails. Beefree can help you get started, with a range of templates for responsive email designs.

How to create newsletters with secure email gateways in mind 

The good news is that you can implement and send out most, if not all, of your newsletter ideas without issue. So long as the emails are well-made and are sent at a reasonable frequency, you’ll be golden. 

Start by first improving your security methods

In general, you should always look at ramping up the security measures in your business. You can use one of the top types of risk assessment matrix to understand your business's threats and how to resolve them. Then, since you already have that information, you can use it to create better newsletters and emails. 

Make sure the personalization feature works

One of the biggest red flags for an SEG is a generic greeting. Adding Dear Sir/Madam at the start isn’t going to fly in today’s world. Even if your email gets through, it’s unlikely the recipient will open it. 

That’s why you need personalization. Linking your email marketing tools to your customer relationship management system means you can offer easy personalization, like addressing your customers by name, or even offering personalized recommendations based on their order history. 

Avoid image-only emails 

Image-only emails are tempting for an email marketer. They’re striking, they look good, and you can fine-tune what they look like in Photoshop or another image editor. 

They can also be a red flag for SEGs.

Thankfully, the solution is simple: enrich your emails. The best part about this approach is that it also improves the accessibility. Improving email accessibility will help ensure that all your customers can engage with your emails on their terms. Those emails will also load faster, look great on all devices, and be more engaging. 

Align your emails with the landing pages 

SEGs look out for suspicious links. A link might be suspicious if there’s a misspelling or if the link doesn’t sound like the content in the email. So, how do you ensure that SEGs don’t see any of your links as suspicious? 

You make them predictable. 

An easy way to do this is to create a landing page from an email. On top of aligning the landing page with the content of the newsletter, you’ll want to: 

  • Make a custom URL for every link that matches the content of the page 
  • Ensure there’s no misspelling
  • Don’t use urgent language around your link

Use 2FA to boost security

Do you need 2FA to get past SEGs? No, but it’s a great way to help protect you and your customers. 

You can protect sensitive data by adding user identity verification. For example, a customer may get an order confirmation email but wants to cancel or change the delivery details. Including a two-factor authentication step ensures only the customer can request changes. 

Building in extra security features puts your customers at ease. It also protects your endpoints and, in turn, your business. So, no, you don’t need 2FA to get past SEGs, but it’s worth looking into for you and your customers’ protection. 

Avoid urgency 

Urgency can be a flag for SEGs. So: 

  • DON’T WRITE IN ALL CAPS
  • Minimize the use of exclamation points

Think of the copy in your newsletter as a chance to win over your audience, not scare them into clicking the link. Doing this will improve your relationship with your customers since they’ve come to you on their terms. It’s also essential to get emails past the SEG.

Key takeaways 

Secure email gateways are a primary defense against spam and phishing attacks, but they can pose a problem for email marketers. By working to understand the security risks associated with email scams, you can then understand what your email needs to make it into inboxes. 

From there, you’ll want to make your emails more personable, accessible, and secure. Once you’ve found that sweet spot, your newsletters will be more likely to get past the secure email gateway and into your audience’s inboxes. 

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From the latest creative design strategies that inspire your next campaign to industry best practices and tech advancements, our newsletter is the go-to for all things creation.

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