JPG to PNG Converter

What actually happens when you convert JPG to PNG

A JPG file does not store pixels directly. It stores a compact mathematical description of the image (blocks of 8×8 pixels turned into frequencies, with the fine detail rounded away). To make a PNG, the converter first decodes the JPG back into a full grid of pixels, then encodes that grid with PNG's lossless compression.

Two things follow from this, and it is worth knowing both before you convert:

• The PNG looks exactly like the JPG. Every pixel you see in the JPG is stored in the PNG unchanged. Nothing gets worse, but the detail the JPG had already thrown away does not come back either. Blockiness or colour smearing in the JPG will still be there.
• The PNG is usually much larger. Lossless compression has to keep every pixel exactly, including the noise that JPG had learned to ignore. Photos grow the most, flat graphics the least.

Measured: how much bigger does the file get?

We converted a set of test images with this tool in Chrome, first with the browser's built-in PNG encoder and then with Compress PNG switched on. Sizes are what you would actually download.

Test set and method: JPGs saved at quality 80–90. To keep large photos fast, the converter compresses images up to 6 megapixels automatically; the compressed figures for the 12 MP and 4K photos show what the optimiser achieves when run on them anyway (it took 9–15 seconds each). The photos are a 4K aerial landscape resized to each size; the screenshot, logo and product shot are synthetic graphics. Exact numbers vary with image content, but the pattern holds: photos grow 6–10×, while screenshots and simple graphics grow far less (1.2–4× with compression on).

The takeaway: convert to PNG when you need what PNG offers (transparency, lossless editing, a platform that demands PNG), not to save space or improve a photo. For sharing photos as small files, JPG or WebP stay the better choice.

When converting to PNG makes sense

• You need a transparent background. Logos, signatures, stickers and product cut-outs for slides, Canva, websites or print-on-demand. JPG has no alpha channel, so it can't be transparent.
• You are going to edit the image several times. Each save as JPG adds new compression artefacts. Saving your working copy as PNG freezes the quality where it is. In our 10-save test, a screenshot re-saved as JPG lost visible sharpness around text, while the PNG copy stayed identical.
• A website, app or printer asks for PNG. Some upload forms, icon generators, game engines and print shops only accept PNG.
• Screenshots and text. If you received a screenshot as a JPG and want to annotate it, PNG keeps the sharp edges of your arrows and labels crisp.

Not sure which format fits your case? Our JPG vs PNG comparison walks through photos, logos, screenshots, web and print one by one.

How we keep your images private

Most online converters upload your file to a server, convert it there and send it back. That is slower, and it means a copy of your image exists, at least briefly, on someone else's computer.

JPGPNG works differently. The page you loaded contains the whole converter. When you add a file, your browser reads it from your disk into memory, decodes it, and writes a new PNG, all locally. The only things our server ever sends are the page itself and the PNG optimiser code. You can verify this with your browser's developer tools, or by disconnecting from the internet after the page loads; conversion keeps working. Read more in our privacy policy.