JPG to PNG Converter

Converting JPG to PNG

This rewrites a JPG as a PNG. It is worth being clear about what that does and does not achieve: PNG is a lossless format, so it will preserve the image exactly as it currently is — including every compression artefact the JPG already contains. Converting does not recover detail that JPG discarded, and it cannot improve quality.

What it does give you is a format that will not degrade further, which is the reason to do it.

Why convert at all

• You are about to edit repeatedly. Each JPG save re-compresses the whole image. Converting to PNG first freezes the current state and stops the accumulation of generation loss across an editing session.
• A system requires PNG. Some print workflows, app store assets, favicon generators and document systems accept only PNG.
• You need to add transparency. You cannot recover transparency the JPG never had, but converting to PNG gives you an alpha channel to work with when you remove a background in an editor.
• Sharp-edged content. If a screenshot or diagram was mistakenly saved as JPG, moving it to PNG stops further damage — though the existing artefacts remain.

Expect a much larger file

PNG stores every pixel losslessly, so a photograph typically becomes 5 to 10 times larger. A 2 MB JPG can easily become a 15 MB PNG. There is a certain irony here: PNG must now losslessly encode all the compression artefacts the JPG introduced, and that noise compresses poorly.

Note the last two rows: for images with flat colour and sharp edges, PNG is genuinely smaller as well as sharper. It is only photographs where the size penalty applies.

Do not use PNG for photos on the web

Because of that size difference, converting web photographs to PNG is usually a mistake. It multiplies page weight for no visible benefit, slows loading, and hurts Core Web Vitals scores. For web delivery, keep photographs as JPG or move them to WebP, which is smaller than both.

The artefact question

JPG compression works in 8x8 pixel blocks, and at lower quality settings those blocks become visible — particularly as blockiness in smooth gradients like skies, and as coloured fringing around sharp edges. Converting to PNG preserves all of that faithfully. If you zoom in on a converted image and see mottling around text, that damage came from the original JPG and no format change will remove it.

There are tools that attempt to smooth JPG artefacts, but they work by blurring, which removes real detail alongside the noise. Recovering the original is not possible — the information was discarded at the first save.

PNG bit depth and colour

PNG supports 8-bit and 16-bit channels, palette-based colour for images with 256 or fewer colours, and full alpha transparency. A JPG is always 8 bits per channel in full colour, so converting produces a 24-bit PNG. If your image genuinely uses few colours — a converted logo, say — running it through a palette optimiser afterwards can reduce the file dramatically without any further quality loss.

Runs entirely in your browser

Conversion happens locally using the Canvas API. Your images are not uploaded, so there is no server-side size limit and no copy of your files anywhere but your own device. Note that because PNG output is large, converting several high-resolution photos at once uses a fair amount of memory.

Frequently asked questions