If you've ever sent a beautiful animated email and had a colleague reply "the GIF is broken," they were almost certainly reading it in Outlook desktop for Windows. Outlook doesn't break animated GIFs — it freezes them on the first frame. That's a rendering-engine problem, not a bug, and it has a clean fix.
Why Outlook freezes GIFs
Outlook 2007 through 2019 on Windows renders email HTML using Microsoft Word's rendering engine, not a real browser. Word doesn't animate images. So it locks every GIF to frame 1 and displays it as a static picture.
Every other Outlook variant animates GIFs normally:
- Outlook.com (web) — animates ✅
- Outlook for Mac — animates ✅
- Outlook mobile (iOS + Android) — animates ✅
- New Outlook for Windows (2024+) — animates ✅
- Outlook 2007–2019 desktop for Windows — first frame only ⚠️
Litmus estimates that Outlook desktop still accounts for roughly 4–7% of business email opens in 2026. It's a shrinking minority, but if your audience is enterprise, insurance, or government, it's a meaningful chunk.
The fix: MSO conditional comments
Microsoft's own answer to the frozen-GIF problem is a syntax called MSO conditional comments. They let you write HTML that only Outlook sees, and HTML that only non-Outlook clients see. Every other email client treats them as regular HTML comments and ignores them entirely.
The pattern:
<!--[if !mso]><!--> <!-- everyone except Outlook sees this --> <img src="animated.gif" alt="Animated" /> <!--<![endif]--> <!--[if mso]> <!-- only Outlook desktop sees this --> <img src="first-frame.png" alt="Animated" /> <![endif]-->
Outlook loads the PNG. Gmail, Apple Mail, iOS, and every other client load the animated GIF. Same email, two branches, one send.
Where the static PNG comes from
Two options:
- Generate it from frame 1 of the GIF. This is what most brands do because the frozen frame Outlook shows anyway looks the same as your intentional PNG. Any image host that gives you an HTTPS URL works.
- Design a custom cover. Pick a still that reads as "this is designed" rather than "this is a paused animation." A subtle "▶ Tap to see" overlay works well.
Gifmailer serves both automatically. When we render a GIF at /api/public/gif/abc123.gif, we also serve the crisp first frame at /api/public/gif/abc123.png — no extra hosting.
Full paste-ready snippet
Drop this into any ESP's HTML block, or into a raw HTML compose in Outlook.com:
<!--[if !mso]><!-->
<a href="https://your-link.com" style="text-decoration:none">
<img src="https://gifmailer.com/api/public/gif/abc123.gif"
alt="Announcing our launch" width="600"
style="display:block;width:100%;max-width:600px;height:auto;border:0" />
</a>
<!--<![endif]-->
<!--[if mso]>
<a href="https://your-link.com" style="text-decoration:none">
<img src="https://gifmailer.com/api/public/gif/abc123.png"
alt="Announcing our launch" width="600"
style="display:block;width:100%;max-width:600px;height:auto;border:0" />
</a>
<![endif]-->Does this hurt deliverability?
No. MSO conditional comments are inert HTML — they don't trip spam scoring in Gmail, Outlook, or any major inbox provider. Every major ESP (Mailchimp, HubSpot, Klaviyo, Customer.io, Iterable) supports pasting the snippet as-is into their HTML blocks.
What if I use an ESP that strips comments?
A few no-code editors (Mailchimp's drag-and-drop, some HubSpot templates) sanitize conditional comments out of the output. In that case, either:
- Use the ESP's "Custom HTML" or "Code Your Own" block, which preserves the comments.
- Accept that Outlook will show frame 1 of your GIF (which is fine if frame 1 is on-brand).
Alternative: just design a good first frame
If MSO comments are more complexity than you want, remember Outlook already shows frame 1. Design that frame like a hero image — logo visible, message legible, CTA in view. Roughly 70% of Gifmailer users skip the fallback branch and just make sure frame 1 stands on its own. Both approaches work.
TL;DR
- Outlook desktop freezes GIFs on frame 1. Everything else animates them.
- Wrap the GIF in
<!--[if !mso]>and serve a PNG inside<!--[if mso]>. - Or design a great first frame and skip the fallback.
- Gifmailer serves both the GIF and the PNG automatically from one URL.
See our full email client compatibility matrix or generate an Outlook-safe email in one click at gifmailer.com/outlook-animated-email.