What is the impact of large GIF file sizes in marketing emails on deliverability and user experience?

Summary

The impact of large GIF file sizes in marketing emails is multifaceted, affecting deliverability and user experience. While some suggest CDNs mitigate direct deliverability issues by hosting images, the overall email size, driven by GIFs, remains critical. Several sources note that exceeding size limits in email clients like AOL can lead to spam filtering. User experience suffers from slow loading times, particularly on mobile, potentially leading to abandonment. Optimizing GIFs through compression, reduced colors, and frame rates is consistently recommended. Audience considerations, accessibility, and bandwidth costs also play a significant role. HBO Max's example suggests flexibility depending on the audience, but generally, balance between visual appeal and email performance is essential.

Key findings

  • CDN Impact: Using a reputable CDN can reduce the direct impact of image size on deliverability when loading images via `img src`.
  • Email Size Limits: Overall email size, influenced by GIFs, significantly impacts deliverability, with some email clients having strict limits (e.g., AOL's 35k limit).
  • Mobile Performance: Large GIFs cause slow loading times, particularly on mobile devices, negatively affecting user experience and engagement.
  • Optimization Benefits: Optimizing GIFs through compression, reduced colors, and frame rates improves loading times and user experience.
  • Audience Consideration: The suitability of heavy GIFs depends on the audience, with B2B audiences potentially preferring smaller, less animated GIFs.
  • Accessibility Issues: Image-laden messages can create accessibility issues, requiring alt text and alternative content.
  • Bandwidth Costs: Large GIFs consume bandwidth, which can be a cost consideration for recipients on metered data plans.

Key considerations

  • Optimize for Mobile: Prioritize optimizing GIFs for mobile devices to ensure fast loading times and a positive user experience.
  • Monitor Overall Size: Monitor the overall email size, including all images and content, to avoid exceeding email client limits.
  • Compress GIFs: Use compression tools and techniques to reduce GIF file sizes without significantly sacrificing visual quality.
  • Limit Colors and Frames: Reduce the number of colors and frames in GIFs to further reduce file size.
  • Consider the Audience: Tailor GIF usage and size to the target audience, considering their devices, bandwidth limitations, and preferences.
  • Address Accessibility: Provide alt text and ensure the message remains understandable even without the GIF.
  • Use CDNs: Host images on a reputable CDN to improve loading times and potentially reduce deliverability risks.

What email marketers say
11Marketer opinions

Large GIF file sizes in marketing emails can significantly impact both deliverability and user experience. While some sources suggest flexibility in GIF size depending on the audience (e.g., HBO Max's use of large GIFs), several experts emphasize the importance of optimization. Large GIFs can lead to slow loading times, particularly on mobile devices, potentially frustrating recipients and causing them to abandon the email. Some email clients may also clip overly large emails. Optimizing GIFs involves reducing colors, dimensions, and frame rates, as well as using compression tools. Considerations around accessibility should also influence the usage of GIFs.

Key opinions

  • Loading Time: Large GIFs increase loading times, leading to poor user experience and potential abandonment.
  • Deliverability Impact: Excessively large email sizes, often due to unoptimized GIFs, can impact deliverability, as some email clients may clip messages.
  • Audience Matters: The suitability of heavy GIFs depends on the audience; animated GIFs might not perform well with B2B audiences.
  • Accessibility: Image-laden messages can pose accessibility issues.
  • Optimization Techniques: Reducing colors, dimensions, and frame rates can significantly reduce GIF file sizes.
  • Compression Tools: Compression tools can reduce GIF file sizes without significantly impacting quality.

Key considerations

  • Target Audience: Consider the target audience when deciding on GIF size and complexity. B2B audiences may prefer smaller, less animated GIFs.
  • Mobile Optimization: Optimize GIFs for mobile devices to ensure quick loading times and a positive user experience.
  • File Size Limits: Be aware of email client size limits and optimize GIFs to avoid clipping or delivery issues.
  • Accessibility: Address accessibility concerns by providing alt text for GIFs and ensuring the message is still understandable without the visuals.
  • Visual Quality: Balance file size reduction with maintaining acceptable visual quality of the GIF.
  • Loading Speed: Prioritize fast loading speeds to keep recipients engaged and prevent abandonment.
Marketer view

Email marketer from Reddit shares that slow-loading GIFs can frustrate recipients, leading them to abandon the email. Optimizing GIFs for faster loading times is crucial to maintain engagement.

November 2022 - Reddit
Marketer view

Email marketer from Litmus explains that excessively large email sizes, often due to unoptimized GIFs, can impact deliverability. Some email clients may clip messages exceeding certain size limits, potentially hiding crucial content or calls to action.

May 2023 - Litmus
Marketer view

Email marketer from Sendinblue shares that large images and GIFs are one of the main reasons why emails don't load quickly. Optimizing images is critical for improving the user experience.

January 2023 - Sendinblue
Marketer view

Email marketer from Hubspot explains that using compression tools can significantly reduce GIF file sizes without noticeably impacting quality, ensuring faster loading times and improved user experience.

November 2023 - HubSpot
Marketer view

Email marketer from Email on Acid shares that large GIF file sizes can lead to slow loading times, especially on mobile devices. They suggest limiting colors, reducing dimensions, and optimizing the number of frames to reduce file size without sacrificing visual quality.

April 2021 - Email on Acid
Marketer view

Email marketer from Email Geeks shares that HBO Max regularly sends emails with GIFs exceeding 5MB, suggesting that it's reasonable to expand the image size limit while keeping the audience in mind.

June 2021 - Email Geeks
Marketer view

Email marketer from Neil Patel's blog explains that optimizing images, including GIFs, is crucial for email loading speed. Large files increase loading times, leading to poor user experience and potential abandonment. Compressing GIFs without significant quality loss is recommended.

September 2024 - Neil Patel
Marketer view

Email marketer from StackOverflow explains that reducing the number of colors, limiting the frame rate, and cropping unnecessary areas can significantly reduce GIF file sizes, improving loading times.

January 2025 - StackOverflow
Marketer view

Email marketer from ActiveCampaign shares that the key is to create emails that load quickly and display properly, no matter what size screen your recipient views it on. Optimizing images is a key part of the mobile-first design process.

March 2024 - ActiveCampaign
Marketer view

Email marketer from GIPHY shares that using a limited color palette and ensuring efficient compression helps in creating GIFs suitable for email marketing, balancing visual appeal with file size limitations.

August 2021 - GIPHY
Marketer view

Email marketer from Email Geeks shares that the suitability of heavy GIFs depends on the audience. Animated GIFs might not perform well with B2B audiences, and there are accessibility issues with image-laden messages.

February 2023 - Email Geeks

What the experts say
2Expert opinions

The impact of large GIF file sizes on email deliverability and user experience is a nuanced issue. One perspective suggests that if images are loaded via `img src` and served from a reputable CDN, the file size has no direct impact on deliverability. Only the link resides within the email itself. However, another perspective highlights that large image sizes contribute to overall email size, which can negatively affect deliverability. Email programs like AOL may have strict size limits (e.g., 35k), and exceeding these limits can lead to emails being marked as spam. Additionally, large GIFs consume bandwidth, which can be a cost concern for recipients with metered data plans.

Key opinions

  • CDN Impact: Using a reputable CDN to host images loaded via `img src` can mitigate direct deliverability impacts related to file size.
  • Email Size Limits: Overall email size, influenced by image sizes, is a factor in deliverability; some email programs impose strict limits.
  • Bandwidth Cost: Large GIFs consume bandwidth, which can be a financial burden for recipients on metered data plans.

Key considerations

  • Hosting Method: Choose an appropriate hosting method for images (e.g., CDN) to minimize deliverability risks.
  • Email Size Awareness: Be mindful of the overall email size, including images and other content, to avoid exceeding email program limits.
  • Recipient Data Costs: Consider the potential bandwidth costs for recipients when using large GIFs, particularly those with metered data plans.
Expert view

Expert from Email Geeks explains that if the image is loaded through `img src`, the image size has zero impact on deliverability, assuming the CDN platform has a good reputation. The only piece inside the email is the link.

August 2022 - Email Geeks
Expert view

Expert from Word to the Wise shares that image sizes, especially background images and GIFs, are a common culprit for increased email size. She notes that some programs, like AOL, have a limit of around 35k, so going over that is a guaranteed ticket to the spam folder. She also shares that some mobile users still have metered data, so the bandwidth of your images is a cost to your recipients.

August 2024 - Word to the Wise

What the documentation says
4Technical articles

Email service providers like Gmail, Outlook, Campaign Monitor, and Mailchimp highlight that large GIF file sizes in marketing emails can negatively impact deliverability and user experience. While some platforms may not have explicit image size limits, exceeding overall message size limits can lead to delivery issues or reduced performance. Optimization of GIFs, including reducing complexity and file size, is crucial for ensuring better compatibility, open rates, conversions, and overall email performance.

Key findings

  • Overall Size Matters: Exceeding overall email size limits, which includes images, can cause delivery issues, even if there isn't a specific image size restriction.
  • Impact on Engagement: Large GIF files contributing to increased email size can negatively impact open rates and conversions.
  • Deliverability Risks: Exceeding message size limits in platforms like Outlook can result in delivery failure.
  • Optimization Benefits: Optimizing images and GIFs ensures better compatibility and user experience across different platforms.

Key considerations

  • Monitor Overall Size: Keep the overall email size low, considering the combined size of all elements, including images and GIFs.
  • Optimize GIFs: Prioritize GIF optimization techniques to reduce file size while maintaining visual quality.
  • Platform Compatibility: Ensure compatibility across different email service providers and devices by adhering to recommended size guidelines.
  • Balance Performance and Visuals: Strike a balance between visual appeal and email performance by carefully managing GIF complexity and file size.
Technical article

Documentation from Campaign Monitor explains that large GIF files contribute to increased email size, which can negatively impact open rates and conversions. Reducing the complexity and size of GIFs is suggested for better performance.

June 2023 - Campaign Monitor
Technical article

Documentation from Mailchimp shares that while there isn't a strict image size limit, overall email size should be kept low for optimal deliverability. Optimizing GIFs is crucial for balancing visual appeal with email performance.

June 2023 - Mailchimp
Technical article

Documentation from Google explains that while Gmail doesn't explicitly block large emails based solely on image size, exceeding overall message size limits can cause delivery issues. Optimizing images and GIFs ensures better compatibility and user experience.

April 2023 - Google Support
Technical article

Documentation from Microsoft shares that Outlook has message size limits that include images. Exceeding these limits can result in delivery failure. Compressing GIFs and other images is recommended to stay within acceptable size ranges.

February 2025 - Microsoft Support