JPG to PNG

This tool takes a JPG (or JPEG) image and re-encodes it as a PNG file. The output preserves the image's pixel dimensions and content exactly, because PNG's compression is lossless.

Two things worth knowing. First, converting a JPG to PNG does not add transparency: a JPG never contains transparency, so the converted PNG shows the same opaque background as the original. Second, because PNG is lossless, the file will usually be larger than the JPG you started with — that is the trade-off for perfect quality.

The right mental model: PNG is for images that need sharp edges or transparency (logos, graphics, screenshots), while JPG is for photos where smaller size matters more than pixel-perfection.

The image is decoded in the browser and drawn onto a canvas — the HTML element that gives the browser direct access to pixel data. The canvas is then encoded as a PNG blob using the browser's native PNG encoder.

Because PNG encoding is lossless, every pixel of the source image is preserved in the output. The converted file is generated in memory and offered as a download.

Everything runs locally with the HTML5 canvas API: no upload, no server, and no file size limit beyond what your device can handle in memory.

JPG and PNG store images in fundamentally different ways. JPG uses lossy compression that discards fine detail to shrink files, tuned for photographs. PNG uses lossless compression that stores every pixel exactly, which is why text and hard edges stay sharp but files are larger.

Converting between them is a re-encode: the pixels are decoded from the source and re-encoded in the target format. Going JPG-to-PNG never recovers detail the JPG already discarded — the output is exactly as good as the source, no better.

Transparency is a common misconception: PNG supports an alpha channel, but a JPG has none, so converting a JPG to PNG cannot create transparency. The output carries the same opaque background as the original.