Chat inline image previews: WebP support (still + animated) #651

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opened 2026-10-10 22:33:54 +00:00 by sky_line · 2 comments

sky_line commented

2026-10-10 22:33:54 +00:00

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Chat inline image previews (#265) handle PNG, JPEG and GIF (still and animated). WebP links show no preview, even though llchatimagecache.cpp already recognises WebP from its file signature (MAGIC_WEBP). Many image hosts and CDNs now serve WebP by default, so previews are missing for a growing share of links.

Scope

Decode still and animated WebP for the inline preview and the full-size preview floater. Animated WebP follows the GIF path: frame timing, loop count and the same frame/memory caps.
Accept image/webp from the Content-Type header, the file signature and the .webp extension. Same URL policy as now.
Untrusted input. Use a current libwebp release; the 2023 CVE-2023-4863 heap overflow was in libwebp's decoder. Check the dimension and size limits before decoding, as the PNG/JPEG paths do.
Build libwebp the same way on Linux, Windows (cross-build) and macOS. Pin it with a hash. Credit it under its BSD licence in the licences/about text.

Optional follow-up, not in this ticket: WebP for texture/snapshot upload and for local image loading.

Chat inline image previews (#265) handle PNG, JPEG and GIF (still and animated). WebP links show no preview, even though `llchatimagecache.cpp` already recognises WebP from its file signature (`MAGIC_WEBP`). Many image hosts and CDNs now serve WebP by default, so previews are missing for a growing share of links. ## Scope - Decode **still and animated** WebP for the inline preview and the full-size preview floater. Animated WebP follows the GIF path: frame timing, loop count and the same frame/memory caps. - Accept `image/webp` from the Content-Type header, the file signature and the `.webp` extension. Same URL policy as now. - **Untrusted input.** Use a current libwebp release; the 2023 CVE-2023-4863 heap overflow was in libwebp's decoder. Check the dimension and size limits *before* decoding, as the PNG/JPEG paths do. - Build libwebp the same way on Linux, Windows (cross-build) and macOS. Pin it with a hash. Credit it under its BSD licence in the licences/about text. Optional follow-up, not in this ticket: WebP for texture/snapshot upload and for local image loading.

sky_line added the

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2026-10-10 22:33:54 +00:00

sky_line added this to the Slipstream project

2026-10-10 22:33:54 +00:00

sky_line commented

2026-10-10 22:34:13 +00:00

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