Free Image Converter

Understanding the two compression families explains every "which format?" decision:

JPEG (lossy) divides the image into 8×8 pixel blocks and converts each into frequency patterns (a discrete cosine transform). It then throws away the high-frequency detail your eye barely notices — subtle texture, faint gradients — keeping the shapes and colours you do. That is why photographs compress beautifully but sharp edges suffer: text and logos develop the familiar fuzzy "ringing" halo, and every re-save discards a little more. The quality slider controls how aggressively detail is discarded.

PNG (lossless) never discards anything. It predicts each pixel from its neighbours and stores only the difference, then compresses those differences with the same DEFLATE algorithm used in ZIP files. Flat areas and repeating patterns — screenshots, charts, UI graphics — compress to almost nothing, while photographs (where every pixel differs from its neighbour) barely compress at all. PNG also supports true transparency, which JPEG cannot.

WebP (both) is the modern replacement that borrows techniques from video compression. In lossy mode it typically produces files 25–35% smaller than an equivalent-quality JPEG; in lossless mode it usually beats PNG too, and it supports transparency in both modes. When in doubt for web use, WebP is the right answer.

This tool does the conversion with your browser's own Canvas API — the image is decoded and re-encoded on your device, never uploaded. That makes it safe for IDs, medical documents, or anything else you would not hand to a random file-conversion server.

Images are usually the heaviest thing on a web page, and the largest image is very often the "Largest Contentful Paint" element that Google's Core Web Vitals measure. If you are converting images for a website, three habits deliver most of the win:

• Convert photos to WebP at ~80% quality. A 1.2 MB JPEG straight from a phone typically becomes 150–300 KB with no visible difference on screen.
• Resize before you compress. A 4000-pixel-wide photo displayed in a 800-pixel column wastes 25× the pixels. Scale the image to roughly the largest size it will be displayed at (2× for high-DPI screens) before converting.
• Keep PNG for what PNG is good at. Screenshots, diagrams, and logos stay crisp and small as PNG; converting them to JPEG adds artefacts and often increases file size.

A practical workflow with this tool: drop in the original, pick WebP, nudge the quality slider down until the preview shows visible degradation, then step one notch back up — that is your optimum for that image.