How many email clients support background-size?

It works in 17 of 21, partial in 3, not supported in Outlook Classic.

Does background-size work in Yahoo Mail iOS?

background-size works in Yahoo Mail iOS. Closest to Yahoo Mail Android: Yahoo Mail iOS, which agrees on 284 of the 297 features both are tested on.

background-size in Yahoo Mail Android

Works background-size works in Yahoo Mail Android.

Works in 17 of 21 · partial in 3 · not supported in 1

Which clients

Works: Gmail, Outlook 365, Outlook (New), Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, AOL Mail, Fastmail, Superhuman
Partial: Gmail Android, Gmail iOS, Yahoo Mail
Not supported: Outlook Classic

The fix for the clients that need it

Needed in 4 of 21: Outlook Classic, Gmail Android, Gmail iOS and 1 more.

Outlook ignores background-size; use VML or sized images

instead

15 lines

<td background="bg.jpg" bgcolor="#333333" width="600" height="400" valign="top"
    style="background-color: #333; background-image: url('bg.jpg');
           background-size: cover; background-position: center; background-repeat: no-repeat;">
  <!--[if gte mso 9]>
  <v:rect xmlns:v="urn:schemas-microsoft-com:vml" fill="true"
    stroke="false" style="width:600px; height:400px;">
    <v:fill type="frame" size="100%,100%" src="bg.jpg" color="#333333" />
    <v:textbox inset="0,0,0,0">
  <![endif]-->
  <div>Content</div>
  <!--[if gte mso 9]>
    </v:textbox>
  </v:rect>
  <![endif]-->
</td>

Show the original

before

3 lines

<td style="background: url('bg.jpg') center/cover no-repeat;">
  Content
</td>

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What Yahoo Mail Android does with background-size

caniemail record, tested upstream 28 Feb 2019

Partial. Does not support multiple values. The comma between two values is removed.

Your next question

Every feature in Yahoo Mail Android · background-size in every client

Questions

How many email clients support background-size?: It works in 17 of 21, partial in 3, not supported in Outlook Classic.
Does background-size work in Yahoo Mail iOS?: background-size works in Yahoo Mail iOS. Closest to Yahoo Mail Android: Yahoo Mail iOS, which agrees on 284 of the 297 features both are tested on.

To see what in your email Yahoo Mail Android does not support, paste the whole email.

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caniemail (MIT) via @emailens/engine 0.18.22 · tested upstream 28 Feb 2019 · data last changed 10 Nov 2026 · Outlook (New) cells are the engine's mapping