Outlook VML Background Generator
Builds a background image Outlook Classic draws as VML and the other 20 clients read as CSS, with a solid colour for images off. Copy the code; nothing leaves your browser.
@emailens/engine 0.18.22 · data last changed 10 Nov 2026
Outlook reads the VML <v:image>; every other client reads the CSS background-image. With images off, both fall back to your solid color.
<!-- Bulletproof background image: Outlook (VML) + all other clients -->
<div style="background-color:#1e1b4b;">
<!--[if mso]>
<v:image xmlns:v="urn:schemas-microsoft-com:vml" fill="true" stroke="false" style="width:600px;height:300px;" src="https://images.unsplash.com/photo-1579546929518-9e396f3cc809?w=1200&auto=format&fit=crop&q=80" />
<v:rect xmlns:v="urn:schemas-microsoft-com:vml" fill="true" stroke="false" style="position:absolute;width:600px;height:300px;">
<v:fill opacity="0%" color="#1e1b4b" />
<v:textbox inset="0,0,0,0">
<![endif]-->
<div>
<!--[if mso]><table role="presentation" border="0" cellpadding="0" cellspacing="0" width="600"><tr><td><![endif]-->
<div style="background-image:url('https://images.unsplash.com/photo-1579546929518-9e396f3cc809?w=1200&auto=format&fit=crop&q=80');background-position:center center;background-size:cover;background-color:#1e1b4b;max-width:600px;height:300px;">
<table role="presentation" border="0" cellpadding="0" cellspacing="0" width="100%" height="300">
<tr><td align="center" valign="middle" style="padding:24px;">
<h1 style="margin:0;font-family:Arial,sans-serif;font-size:28px;line-height:36px;font-weight:bold;color:#ffffff;text-align:center;word-break:break-word;">Summer sale is live</h1>
</td></tr>
</table>
</div>
<!--[if mso]></td></tr></table><![endif]-->
</div>
<!--[if mso]>
</v:textbox>
</v:rect>
<![endif]-->
</div>Change the background and the checker opens it with you. Or open the checker and paste your whole email there: five clients, no account.
No signup · Five clients free, Outlook Classic included · All 21 with an account
Which clients need an account
Gmail Android, Gmail iOS, Outlook 365, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, AOL Mail, Fastmail, Superhuman open with a free account.
The checker needs a computer screen.
Your next question
Other free tools: HTML Email Checker · CSS Support Lookup · CSS Inliner · Dark Mode Preview · Outlook Ghost Table Generator · Bulletproof Button Generator · Client Targeting Generator · Email Rendering Playground
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The open-source CLI checks every template for VML and Outlook problems, free: npx @emailens/cli lint email.html
(CLI docs).
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Questions
Why don't background images show in Outlook?
Desktop Outlook on Windows uses the Microsoft Word rendering engine, where the CSS background-image property is not supported. The fix is VML: a <v:image> and <v:rect> block, wrapped in an <!--[if mso]--> conditional comment, that Word does understand.
What is VML in email?
VML (Vector Markup Language) is a legacy Microsoft markup that Outlook's Word engine still renders. Email developers use it to reproduce rounded buttons and background images that CSS alone can't deliver in Outlook.
Do I still need a fallback color?
Yes. Many clients block remote images until the recipient clicks 'show images', and accessibility settings can disable them entirely. A solid fallback background color keeps overlay text readable when the image doesn't load.