CSS property · data last changed 10 Nov 2026
[width] in email clients
Works in 18 of 21. Not supported in HEY Mail. Partial in Outlook Classic. Untested in Superhuman.
Safe to leave in: where it is not supported, the email renders the same.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
- Buggy. Percentage width on
<img>elements are based on the physical file's width, not on the parent element's width. - Buggy. Sizes set in attributes don't scale in 120 dpi mode.
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[width] is not among the 24 features we have screenshotted on real installs. The ones we have →
All 21 clients, problems first
| Client | Support |
|---|---|
| HEY Mail | Not supported |
| Outlook Classic | Partial See caveat 1 |
| Superhuman | Untested |
Works in 18: Gmail, Gmail Android, Gmail iOS and 15 more. Show all
| Client | Support |
|---|---|
| Gmail | Works |
| Gmail Android | Works |
| Gmail iOS | Works |
| Outlook 365 | Works |
| Outlook (New) | Works |
| Outlook iOS | Works |
| Outlook Android | Works |
| Outlook for Mac | Works |
| Apple Mail | Works See caveat 2 |
| Apple Mail iOS | Works |
| Yahoo Mail | Works |
| Yahoo Mail Android | Works |
| Yahoo Mail iOS | Works |
| Samsung Mail | Works |
| Thunderbird | Works |
| Proton Mail | Works |
| AOL Mail | Works |
| Fastmail | Works |
Caveats (2)
- 1. Outlook Classic: Buggy. Percentage width on
<img>elements are based on the physical file's width, not on the parent element's width. Buggy. Sizes set in attributes don't scale in 120 dpi mode. - 2. Apple Mail: The
widthattribute is ignored on CID embedded images. See #171.
Caveats as recorded by caniemail (MIT), one entry per wording.
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