Convert JPG to PNG

JPEG and PNG solve two different problems, and the difference is not cosmetic. JPEG is a lossy format. When a camera or an editor writes a .jpg it chops the picture into blocks, converts each block into frequency coefficients, and then rounds those coefficients off according to a quality setting. It usually also throws away three quarters of the colour resolution, keeping full detail only in brightness, because human eyes notice brightness far more than colour. The result is a small file that looks close enough to the original, but the discarded information is genuinely gone. PNG works the other way around: it applies a reversible per-row filter and then general purpose DEFLATE compression, and decoding gives back the exact pixel values that went in. Nothing is approximated.

That distinction is the whole reason people convert. Once your image lives in a PNG, you can open it, edit it, and save it as many times as you like without the picture degrading. In a JPEG workflow every save is a fresh round of quantisation on top of the last one, which is what people mean by generation loss. Crop, save, reopen, adjust the levels, save again, and after enough rounds you can watch the edges around text go crunchy and flat skies break into visible bands. Converting to PNG puts a hard stop on that process at whatever state the image is in today.

Which brings us to the honest part. Converting a JPG to a PNG does not repair anything. It cannot recover the detail JPEG already discarded, because that data was never written to the file you have. If your source image has blocking around high contrast edges, halos and ringing near text, or muddy smearing in a saturated red jumper, the PNG will reproduce all of it perfectly, artifacts included. Perfect reproduction of a damaged picture is still a damaged picture. Anyone selling you a JPG to PNG conversion as a quality upgrade is describing something that is not physically possible.

The second honest caveat is transparency. PNG supports an alpha channel, JPEG does not, and a format conversion cannot invent information that was never in the source. Your PNG will be fully opaque with exactly the background the JPG had. Getting an actual transparent background requires deciding which pixels are subject and which are backdrop, which is a segmentation job rather than a conversion job. Our free background remover does that part and hands you a transparent PNG at the end.

The third thing to expect is size. Because PNG has to store every pixel exactly and because photographic content is full of fine noise that general purpose compression cannot squeeze, a converted photo commonly lands somewhere between three and ten times the size of the JPG it came from. A 2MB holiday photo turning into a 14MB PNG is normal, not a bug. That is the price of lossless, and it is why PNG never replaced JPEG for photographs on the web. For flat colour content the arithmetic flips completely: screenshots of a user interface, charts, logos, diagrams and line art compress beautifully in PNG, often smaller than the JPEG version, and with none of the ringing that JPEG smears around hard edges and text.

So the practical rule is simple. Convert JPG to PNG when something downstream demands PNG, when you are about to keep editing, or when the image is the kind of flat, sharp edged content PNG was designed for. Do not convert a photograph to PNG just to put it on a web page: you will multiply the download size for viewers and gain nothing visible, since the JPEG damage is already baked in. If your goal is a smaller photo rather than a lossless one, staying in JPEG is the right call.