Motion gets exactly one visa into the inbox
Put video in an email and watch most clients strip the player, ignore the tag, or fall back to a still. There is no inbox video standard, and after two decades of nothing, none is coming. A GIF slips past all of that because it travels as a plain image tag, the one element every mail client on earth renders without argument. That accident of history is the entire reason a gif in email works.
It also sets the terms. An image tag gets no buffering, no quality ladder, no play button. The file arrives whole and plays as-is, or it fails, which is why nearly everything on this page comes back to weight.
Three numbers, then everything else
Client quirks number in the dozens. The targets that neutralize most of them number three.
- Roughly 1MB of file, tops. Many senders build to 500KB. Total message weight feeds deliverability scoring, so a bloated hero can cost you inbox placement before anyone sees frame one.
- About 600 to 640px of width. That's the standard template column as of mid-2026. Pixels past it get scaled away by the client, and you still paid for them in kilobytes.
- Gmail's clip line, roughly 102KB of HTML. The meter runs on body markup, not image bytes, meaning the GIF is innocent, but a heavy template can push your unsubscribe link below Gmail's cutoff. The Gmail guide covers it properly.
A GIF's weight is duration times dimensions times palette. Every fix that follows pulls one of those levers, and the small-GIF recipe pulls them harder when the budget is brutal.
Classic Outlook votes with frame one
The desktop Outlook builds from roughly 2007 through 2019 render mail through Microsoft Word, and Word has no concept of animation. Recipients on those builds see your GIF's first frame as a permanent still. The newer family, meaning new Outlook, Outlook.com, and Outlook mobile, animates normally, but corporate IT keeps old desktop installs alive long past their prime.
The discipline that follows: the opening frame has to succeed as a finished graphic. Headline readable, product visible, offer legible at a glance. If the payoff only exists in frame forty, some fraction of your list never learns it existed. The Outlook page maps which builds do what.
Assemble the file to the budget
Bring the source clip (mp4, mov, webm, mkv, and most things a browser can open) to What the GIF. The encode runs on your own machine, inside the tab, so a pre-launch campaign cut never sits on anyone's server, and no signup or watermark stands between you and the download.
- Cut hard. Two to four seconds covers almost any email idea. Trims land on exact frames, and the arrow keys walk the cut one frame per tap, so the loop opens where you decide.
- Crop to the slot. 16:9 or 4:3 for a hero, 1:1 for a column. Ratios are locked, so nothing warps.
- Downscale toward 600px. The single biggest weight saving available, and invisible at template width.
- Thin the motion and the palette. 10 to 15 fps reads smoothly in an inbox, and most footage looks identical at 128 colors, or 64 with dithering smoothing the gradients.
- Let the estimate call it. The projected size recalculates with every adjustment; stop tuning once it reads comfortably under the megabyte.
Two extras earn their keep in email specifically. Up to 3 baked-in text captions (a clean style with a color picker, or classic meme type) keep your offer on the pixels no matter how a client handles live text. And sequencing up to 10 clips into one GIF turns a three-beat product story into a single image slot.
The cheat sheet, hedged accordingly
Platforms adjust their rules quietly, so file every figure below under approximate, mid-2026 edition.
- Gmail: animates, proxies every image through Google's servers, clips message HTML past roughly 102KB.
- Apple Mail: animates on macOS and iOS with no drama.
- Outlook: new Outlook, Outlook.com, and mobile animate; classic desktop shows the first frame only.
- Mailchimp, Klaviyo, HubSpot: all pass GIFs through, with image guidance trending around 1MB.
- Everywhere: write alt text for the image-blockers, and expect an infinite loop, so cut something you can stand on the third lap.
Where the footage spends the whole process
On your computer. The conversion is client-side from drop to download, behaves identically whether the machine is a Mac, a Windows PC, a Chromebook, or a Linux desktop, and keeps functioning with the network unplugged after the first load. There's no account layer at all, which means there's also nothing to leak an embargoed cut. Ads pay for the tool; your files aren't the price.