JPG to PNG Converter

JPG and PNG answer different questions

JPG (technically JPEG, created by the Joint Photographic Experts Group in 1992) is built for photos: millions of colours, smooth gradients, lossy compression tuned to what the human visual system can't see. PNG (Portable Network Graphics, 1996) was invented as a patent-free replacement for GIF. It's lossless, supports alpha transparency, and excels at flat colour, text, and line art. Converting from JPG to PNG doesn't recover detail the JPG threw away — it just locks in whatever the JPG had, losslessly from that point on.

When the conversion is worth doing

• You're going to edit the image further and don't want each save to degrade it (JPEG loses quality on every re-save; PNG doesn't).
• A form or platform requires PNG (some government sites, print services, or image upload endpoints reject JPG).
• You need to sit the image over another background in a slide deck or design file — PNG's transparency is the reason. (Note: a JPG has no transparency to preserve, so you'll need to erase the background yourself in an editor; this tool just changes the wrapper.)
• You want to layer on vector elements or text in a PNG-aware editor without JPEG's 8×8 block artefacts getting sharpened.

When it's a bad idea

Don't convert holiday photos to PNG just because "lossless" sounds better. A 3 MB JPG often becomes a 20–40 MB PNG with no visible improvement, because the photo's detail is already baked in. PNG compression is best on images with large flat-colour areas; on photographs it can easily multiply file size by 10× with zero benefit.

File size expectations

• Photograph: PNG usually 5–15× larger than JPG.
• Screenshot of a UI: PNG often smaller than a JPG at the same visual quality.
• Flat logo: PNG dramatically smaller and sharper.
• Gradient-heavy illustration: PNG larger than JPG but avoids the "banding" JPEG can introduce.

What the converter actually does

Your JPG is decoded by the browser into raw pixel data on a <canvas> element. That pixel buffer is then re-encoded using the browser's native PNG encoder via canvas.toBlob('image/png'). No cloud round-trip, no quality slider, no compression ratio to set — PNG encoding is deterministic.

Shrinking a bloated PNG after conversion

If your PNG output feels too large, two options: (1) run it through a PNG optimiser like pngquant, OptiPNG, or oxipng, which can reduce file size 40–70% losslessly; (2) accept that for photos, PNG is the wrong container — go back to JPG at quality 85 and you'll get a fraction of the size with no visible difference.

Privacy

The conversion runs in your browser — your image bytes are never transmitted over the network. Metadata like EXIF is dropped during the canvas round-trip; if you need to preserve it, use a dedicated image tool.