JPG to PNG converter
This page writes a lossless PNG of whatever the JPEG decoder produced. It is useful when you need a PNG for a tool or site that expects one, when you want to edit a photo without further lossy saves, or when you need an alpha channel to add transparency later. It is not a way to un-JPEG a photo.
Files are converted on your device and never uploaded.
Processed on your device. Files aren’t sent anywhere.
Real reasons to convert a JPEG to PNG
PNG is the format editors, design tools and many upload forms expect. Converting gives you a file that can be saved repeatedly without each save costing more quality, because PNG encoding is lossless.
PNG also carries an alpha channel, so a JPEG converted here can later receive transparency in an editor. The PNG is faithful to the decoded pixels, not to the original camera file - block artefacts and soft edges baked in by the JPEG come along with them.
- Good fit: preparing an image for editing, feeding a tool that requires PNG, stopping lossy re-saves
- Poor fit: shrinking a photo for a web page - keep JPEG or use WebP
- Not a fix: heavy JPEG artefacts stay visible in the PNG
Why the file usually gets bigger
JPEG throws data away to be small; PNG keeps every pixel it was given. A photo converted to PNG commonly grows several times in size. That is expected behaviour, not a defect - if your goal is a smaller file, this is the wrong direction.
Transparency is added, not recovered
The canvas encodes PNG with alpha enabled, so the output has an alpha channel. A JPEG has no transparency to carry over, so the image starts fully opaque; anything transparent is something you add afterwards.
No quality slider — PNG has none
This route offers only the Size steps. There is no quality control for PNG output, because PNG does not discard pixels to compress; the encoder chooses filters and compression instead.
That means the pixels you get are exactly the pixels the decoder drew. The only lever is resizing, which is a real reduction in dimensions rather than a quality compromise.
- Original: width and height unchanged
- 75% / 50%: downscale a large photo before editing or embedding
- 25%: preview tiles; fine detail and text become unreadable
- Resizing uses high-quality smoothing, but it is still resampling - not a lossless operation
When scaling helps
A JPEG straight from a phone can be several thousand pixels wide. If you only need it as a card image, scaling to 50% here produces a smaller PNG than encoding at Original size, and avoids a separate resize step.
Limits and error cases
Up to 10 files per batch, each up to 25 MiB. The pixel ceiling is 40 megapixels, and the engine rejects an image only when both the source and the scaled output exceed it - so a very large photo downscaled to 50% still converts, while the same photo at Original size may not.
A truncated or corrupt JPEG produces a decode error. If the browser cannot allocate the canvas, the conversion reports an out-of-memory failure instead of producing a partial file.
- Decode error: damaged or incomplete JPEG data
- Pixel limit: huge source kept at Original size
- Out of memory: extremely large canvases on constrained devices
Metadata does not travel
The PNG is built from pixels, so EXIF, GPS, camera settings and ICC profile labels are not copied. If you need those details, keep the original JPEG.
Practical workflow for the output
The PNG keeps your original file name with the extension changed, and reports the output width and height. Your JPEG is untouched; the PNG downloads separately, entirely in this tab.
A common pattern: convert once, then edit the PNG repeatedly. Editing and re-saving a JPEG costs quality each time, while PNG round-trips without additional loss.
- Convert a copy, not the camera original
- Edit the PNG, then encode a delivery JPEG or WebP at the end
- Keep the JPEG if you only need a small published file
Everything stays on your device
Decoding, scaling and encoding run locally on a canvas. No upload, no queue, no account - private photos never leave the machine.