WebP is not reliably supported in HTML email. Which clients render it, why most do not, and what formats to use for newsletters instead.
WebP in Email: Support and Alternatives
WebP is the wrong choice for HTML email. Most email clients cannot render it, and email has no <picture> fallback that works everywhere, so a WebP image often shows as nothing at all. This guide explains which clients support WebP, why coverage is poor, and which formats to use for newsletters instead.
For where WebP does belong, see What is WebP? and WebP Browser Support.
Can you use WebP in HTML emails?
You should not use WebP in HTML emails, because support across email clients is unreliable. Apple Mail renders WebP because it uses WebKit, but many widely used clients — including several Outlook versions — do not. An unsupported client typically shows a broken or blank image with no fallback.
Email rendering is far more fragmented than browser rendering, and there is no dependable per-client format negotiation. The safe assumption is that WebP will fail for a meaningful share of recipients.
Which email clients support WebP?
WebP support in email is partial and inconsistent. Apple Mail on macOS and iOS renders it via WebKit. Most other major clients either do not support it or do so unpredictably across versions and platforms.
The rough picture:
- Apple Mail (macOS, iOS) — renders WebP.
- Outlook (desktop, Word-based engine) — does not render WebP.
- Gmail, Yahoo, and others — inconsistent; not safe to rely on.
Because a single newsletter reaches all of these, the lowest common denominator decides the format.
Why doesn't email support WebP?
Email clients lag browsers badly on standards, and many render with old or non-browser engines. Desktop Outlook uses Microsoft Word's rendering engine, which never adopted WebP. Without a universal engine and without a reliable fallback mechanism, modern image formats spread slowly through email.
This is the same reason email still depends on table layouts and inline styles. Format support trails the open web by years.
What image formats should you use in email?
Use JPG for photographs, PNG for graphics and transparency, and GIF for simple animation. These three render in every email client. They are larger than WebP, but universal rendering matters far more than file size in an email.
Format by content:
- Photographs — JPG
- Logos, graphics, transparency — PNG
- Simple animation — GIF
Convert any WebP source back to these with WebP to JPG, WebP to PNG, or WebP to GIF.
Can you convert WebP to an email-safe format?
Convert WebP to JPG or PNG before placing it in an email. If your source assets are WebP, decode them to a universally supported format first, so every recipient sees the image.
Use WebP to PNG for graphics and transparency, or WebP to JPG for photographs. The command-line equivalent is dwebp.
Where to go from here
- WebP Browser Support: Compatibility & Fallback Guide
- WebP vs JPG, WebP vs PNG
- What is WebP? A Complete Guide to the WebP Image Format
- Convert for email: WebP to JPG, WebP to PNG
WebP belongs on websites, not in inboxes. For email, convert to JPG or PNG so every client renders the image, and save WebP for the web pages those emails link to.