How to Prepare Images for Email Newsletters
Email newsletters live in one of the most restrictive rendering environments on the web. Every email client handles images differently: some block them by default, some strip WebP support, and many cannot handle modern formats at all. If you use the wrong image format, your carefully designed newsletter breaks for a chunk of your subscribers.
This guide covers the image formats that work reliably across email clients, optimal file sizes for fast loading, and how to convert your images for maximum compatibility.
Step-by-Step Instructions
- Use only universally supported formats
For email newsletters, only JPG, PNG, and GIF are considered safe across all clients. Outlook, Gmail, Apple Mail, Yahoo Mail, and Thunderbird all support these three formats. Do not use WebP, AVIF, HEIC, or SVG in emails. Even though some clients may render them, the inconsistency makes them unreliable for mass sending.
- Choose JPG for photos, PNG for graphics
Use JPG for hero images, product photos, team headshots, and any photographic content. Use PNG for logos, buttons, icons, and graphics with text or transparency. For animated elements, GIF is the only option in email, but keep animations short and file sizes small.
- Convert your images
Open imageconvert.co and convert any WebP, HEIC, or AVIF images to JPG or PNG. For newsletter photos, use JPG at 80% quality. This provides a good balance between visual quality and file size. Newsletter images do not need to be as high quality as print or website images since they display in a confined email layout.
- Size images for email widths
Most email templates have a content width between 550 and 700 pixels. Size your images to match this width. A full-width hero image should be 600-700 pixels wide. Product thumbnails should be 200-300 pixels. There is no need for retina-size images in email since most clients do not load high-DPI versions.
- Optimize for total email size
Keep total email size including all images under 100 KB if possible, and never exceed 500 KB. Gmail clips emails over 102 KB of HTML. Individual images should be under 50 KB for fast loading, especially for mobile subscribers on cellular data. Use JPG at 75-80% quality to hit these targets.
Why Email Image Support Is So Limited
Email clients render HTML differently from web browsers, and many are years behind in format support. Outlook uses the Microsoft Word rendering engine for HTML, which has notoriously limited image support. Gmail strips certain HTML and CSS features for security. Apple Mail is the most capable, but you cannot design for the most capable client alone.
This is why email developers stick with JPG, PNG, and GIF. These formats have been supported since the earliest days of HTML email, and they work reliably across every client on every platform.
Image Blocking and Alt Text
Many email clients block images by default until the recipient clicks to load them. This means your email needs to make sense even without images visible. Always include descriptive alt text on every image so subscribers understand the content before loading images. Some email clients display the alt text styled with your CSS, making it a design element in its own right.
Hosting Email Images
Email images are typically hosted on a CDN or your email service provider's servers, not embedded in the email. The email HTML references the images via URLs, and the email client loads them when the subscriber opens the email. This means your images need to be in a web-compatible format (JPG, PNG, GIF) and hosted at a reliable URL that will remain accessible for months or years after sending.
Frequently Asked Questions
Can I use WebP images in email newsletters?
No. WebP support in email clients is inconsistent. Apple Mail and some Gmail configurations render WebP, but Outlook, Yahoo Mail, and many mobile clients do not. Stick with JPG and PNG for reliable rendering across all subscribers.
What is the ideal image width for emails?
Size images to your email template width, typically 600-700 pixels for full-width images. For two-column layouts, use 250-300 pixels per column. Do not go wider than your template since the extra pixels add file size without benefit.
How large can images be in an email?
Keep individual images under 50 KB and total email size under 100 KB for best results. Gmail clips emails over 102 KB of HTML content, and large emails load slowly on mobile devices. Compress images aggressively for email.
Convert images to JPG for email