← CSS Support IndexDoes CSS
Does CSS background-size Work in HTML Email?
Specifies the size of background images, supporting keywords like cover and contain.
Quick Answer
Does background-size work in HTML email?
The CSS background-size property is supported in Gmail, Outlook (Mac / Web), Apple Mail, Yahoo! Mail, and others. It is NOT supported in Outlook (Windows). Always include a safe fallback for unsupported clients.
Which Email Clients Support CSS background-size?
CSS support for background-size across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ✓ Yes | ~ Partial | — |
| Outlook (Windows) | ✗ No | ? | — |
| Outlook (Mac / Web) | ✓ Yes | ✓ Yes | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ✓ Yes | ✓ Yes | — |
| Samsung Email | ? | ✓ Yes | — |
| Thunderbird | ✓ Yes | ? | — |
| ProtonMail | ✓ Yes | ✓ Yes | — |
| Fastmail | ✓ Yes | ? | — |
Notes
- #1 Partial. Not supported with non Google accounts. But it can be used in the `background` shorthand property instead.
- #2 Partial. Does not support multiple values. The comma between two values is removed.
- #3 Background images size can be used in VML with the `size` attribute. See [VML documentation](https://docs.microsoft.com/en-us/windows/win32/vml/size-attribute--fill--vml).
Frequently Asked Questions
Related CSS Properties
Test Your Email Now
Paste your HTML and see how it renders in clients that don't support background-size.
Building a new email instead of checking an existing one? MailViewr's Email Builder only lets you use CSS that's known to render across clients, so background-size can't sneak into your markup by accident. Open the Email Builder →