Image Formats Guide
Compare WebP, AVIF, JPEG and PNG by image type, transparency, quality, compatibility and tested output—not generic format rankings.
Updated
The right format depends on what the image contains and how it will be delivered. Photographs, transparent product cut-outs and interface captures expose different weaknesses, so a useful decision starts with the asset—not a league table of format names.
Use this hub to narrow the candidates, then open the detailed reference for encoding behaviour, limitations and a practical test workflow. OptimizePixels processes each candidate in your browser, so the image pixels are not sent to our server.
Choose by requirement
Test WebP first for a broad mix of photographic and graphic web assets.
Compare AVIF for prominent photographs where a measured saving could justify the additional workflow complexity.
Use JPEG when a familiar photographic format or traditional fallback is required.
Use PNG when exact pixels, sharp interface detail or alpha transparency outweigh file-size pressure.
Tune each format independently; equal quality numbers are not equal visual quality.
Three images, three different decisions
Editorial photograph
Faces, hair, foliage and gradients make a useful lossy-encoding test. Compare independently tuned WebP and AVIF outputs at the final display size.
Transparent product image
Soft glass edges and partial transparency require alpha support and inspection over more than one background.
Screenshot or interface
Small labels, flat fills and one-pixel rules reveal lossy damage quickly. Lossless PNG and WebP are sensible first candidates.
Format decision table
Format. Strong first use. Important check
WebP. General web photographs, graphics and transparent assets. Choose lossy or lossless deliberately and inspect the actual output
AVIF. Large photographs and hero imagery. Encoding cost, workflow support and fine-texture treatment
JPEG. Photographs in traditional workflows. No alpha transparency; repeated re-encoding can accumulate damage
PNG. Screenshots, diagrams and transparent graphics. Full-colour photographs can become unnecessarily large
Quality 80 is not the same test across formats
Encoder controls do not share a universal visual scale. Export realistic candidates, compare them at their intended dimensions and record both file size and visible differences. A format only wins when its output works for this image and this delivery context.
Format questions
Is there one best image format for a website?
No. Image content, transparency, required software support and the measured output all affect the decision. WebP is a practical first test for many assets, not a universal winner.
Should an optimized web file replace the source?
Usually not. Keep the best editable or archival source separately and treat each resized, compressed file as a delivery output.
Are format conversions sent to OptimizePixels?
No. The browser performs image processing locally. The website itself must load, but the selected image pixels are not uploaded to our server for conversion.
Test the candidates on your image
Process locally, inspect the output and save only the version that fits the job.