What is WebP?
WebP is a raster image format developed by Google with lossy and lossless compression, transparency, and animation. All major modern browsers support it, and suitable WebP assets are often smaller than JPEG or PNG equivalents.
How WebP works
WebP stores still or animated raster content in a RIFF-based container whose chunks identify image data and optional features. Lossy and lossless coding use different underlying bitstream designs, while alpha, color profiles, and metadata can accompany the pixels. Image pipelines decode a trusted master, choose a mode and quality for each asset class, preserve needed metadata or animation semantics, and serve the result only to compatible clients.
Key facts
- A lossy WebP image can still carry transparency because its alpha plane is represented separately from the lossy color data; edge quality therefore depends on both encodings.
- Extended WebP files can carry ICC color profiles, EXIF, and XMP chunks, but optimization tools may strip optional chunks unless metadata preservation is explicitly configured.
- Animated WebP frames have duration, placement, blending, and disposal behavior. A decoder or converter that reads only the first frame silently turns the asset into a still image.
When WebP matters
Generating WebP variants can reduce page weight while retaining source or fallback formats where compatibility requires them. Lossy settings may introduce artifacts, and animation can offset expected size savings.