A vision-capable GGUF model (gemma-4-26B + mmproj) replied "none" to
real-estate photos because the client sends AVIF, and llama.cpp's mtmd
chat handler decodes data-URIs with stb_image, which has no AVIF/WebP
support — the model silently received no image. _normalize_vision_content
now transcodes any non-stb format to PNG via PIL (which has libavif) before
handing it to the handler. The radeon GME embedder was unaffected (it
already decodes via PIL). Text-only models (gemma-2-9b, no mmproj) are
untouched — the image is still flattened, since they have no vision tower.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014S8VtAvG499SsCbeESRK7V