Every image you publish forces a choice of format, and the wrong choice can make a file ten times larger than it needs to be — or visibly degrade something that should look crisp. Here's how the web's three main formats actually differ, and simple rules for choosing between them.
JPEG: the universal photograph format
JPEG (or JPG — same thing) has been the standard for photographs since the early 1990s. It uses lossy compression tuned to how human vision works: we're good at noticing brightness changes, bad at noticing subtle color shifts, so JPEG discards color detail first.
Strengths: excellent compression for photos and anything with soft gradients; supported literally everywhere — every browser, email client, photo frame and printer kiosk on Earth.
Weaknesses: no transparency support; sharp edges (text, line art) get visible "ringing" artifacts; quality degrades every time you re-save it.
Use it for: photographs headed anywhere compatibility matters — email, marketplaces, older systems.
PNG: the lossless workhorse
PNG compresses without discarding any data — the decoded image is pixel-for-pixel identical to the original. That precision comes at a price: a photograph saved as PNG is often 5–10× the size of a visually identical JPEG.
Strengths: perfect reproduction; full transparency (alpha channel); sharp edges stay sharp — ideal for screenshots, UI graphics, logos and diagrams.
Weaknesses: enormous file sizes for photographic content.
Use it for: screenshots, logos, icons, charts, any graphic with text, and anything that needs a transparent background.
WebP: the modern default
WebP, developed by Google, does both lossy and lossless compression and supports transparency. In lossy mode it typically produces files 25–35% smaller than an equivalent-quality JPEG; in lossless mode it usually beats PNG too. Every modern browser has supported it for years.
Strengths: smallest files at equal quality; transparency support; one format covers both photo and graphic use cases.
Weaknesses: spotty support in older desktop software and some email clients; if your workflow round-trips images through many tools, JPEG/PNG are safer.
Use it for: anything displayed on the web — hero images, blog photos, product shots, thumbnails.
Three rules that cover 95% of cases
- Publishing to your own website? Use WebP. Smallest files, universal browser support.
- Sending to other people or other systems? Use JPEG for photos — nothing else is as universally accepted.
- Screenshot, logo, or anything with text or transparency? Use PNG (or lossless WebP for the web).
Converting between formats
Conversion is trivial with a browser-based tool: upload in one format, choose another as output. Two cautions: converting PNG → JPEG flattens transparency onto a white background, and converting an already-compressed JPEG to a higher-quality setting doesn't restore lost detail — it just makes the file bigger. When possible, always convert from the highest-quality source you have.
Compress your images now
Ready to put this into practice? Use the free WebPcompress compressor — it runs entirely in your browser, handles 20 images at a time, and your photos never leave your device.