Why does enterprise chat reject my GIF yet accept a shorter MOV of the same joke?
Queries like enterprise wechat gif too large, dingtalk attachment limit, slack upload size, email attachment 25mb, and gif larger than video describe the same physics: GIF stores near-raw frames with limited temporal compression, so wide, long, high-FPS loops become hundreds of megabytes in seconds. MOV can carry H.264 inter-frame compression that keeps the loop readable while dropping bytes enough to pass upload scanners. If you mux without trimming, you simply wrap a bloated frame stack—nothing magical happens. Transparent GIFs with sloppy matting can grow instead of shrink when converted poorly, so compare before-and-after byte totals. MOV does not redact ticket numbers glowing in the UI; compliance still applies. For ops, log checksums per thread so two teammates do not overwrite each other's reaction.mov in the same folder.
IM-safe path: oversized GIF to gateway-friendly MOV
- Read GIF width, frame count, and duration from properties; if above your IM guidance, pre-trim to under three seconds and remove duplicate static frames before the browser pass.
- Export a narrow-width, moderate-bitrate MOV, compare byte size against the GIF, then lower FPS before touching extreme GOP settings.
- Send test files to your own account and a colleague on the target IM client, note any server-side recompression or alpha loss, then register hashes to prevent silent overwrites.