JPG to PNG Converter
Converting JPG to PNG gives you a lossless container, not a better image. The compression damage in the source is already baked into the pixels, and PNG will faithfully preserve every artefact. There are still good reasons to do it, and it is worth being clear about which ones are real.
How to use it
- Drop in a .jpg or .jpeg file.
- The image is decoded and re-encoded as PNG using the browser native encoder.
- The .png downloads immediately.
Expect the file to get substantially larger
This surprises people, so it is worth stating plainly: a 400 KB JPG commonly becomes a 2 to 4 MB PNG. PNG compression is lossless, so it has to encode every pixel exactly, including the JPEG artefacts.
Those artefacts actively work against PNG. The format compresses best on images with large runs of identical pixels, and JPEG decoding produces subtle noise across every flat area, so almost no two adjacent pixels are exactly equal. A flat grey background that PNG would normally store in almost no space becomes thousands of very slightly different greys.
What the conversion cannot do
It cannot remove blocking, ringing, or colour bleeding. Once JPEG has discarded high-frequency detail, that information does not exist anywhere in the file. What you see in the decoded image is the whole of what remains, and PNG preserves it exactly.
It also cannot add transparency. The conversion produces a fully opaque PNG. You can erase areas afterwards in an editor to create an alpha channel, and that is a legitimate reason to convert first, but the conversion itself does not create transparency.
When converting is genuinely the right move
The strongest case is as a working format during editing. Every time you save a JPG you re-encode it, and repeated open-edit-save cycles visibly degrade an image. Converting once to PNG and editing in PNG stops the accumulation, even though the starting point is already imperfect.
It is also the right call when a target system demands PNG. Some print workflows, some icon pipelines, and a number of document and presentation tools either require PNG or handle it more predictably. And if you intend to cut out a background to produce a transparent asset, you need a format with an alpha channel to save into.
At a glance
| Accepted input | .jpg, .jpeg |
|---|---|
| Output | .png, lossless, fully opaque |
| Typical size change | Three to ten times larger |
| Engine | Canvas 2D, browser native PNG encoder |
Frequently asked questions
Will this improve the quality of my JPG?
No. It preserves the current quality without further loss. The detail JPEG already discarded cannot be recovered by any format conversion.
Why is the PNG so much bigger than the JPG?
PNG is lossless, so it stores every pixel exactly, including the compression noise JPEG introduced. That noise defeats the run-length style compression PNG relies on, so flat areas that should compress well no longer do.
Does the PNG have a transparent background?
No. The output is fully opaque. JPG carries no transparency information, so there is nothing to restore. You can add transparency afterwards in an image editor.
Is there any point converting if the file only gets bigger?
Yes, when you are about to edit. Repeatedly saving as JPG compounds the damage with every save. Working in PNG freezes the loss at its current level.
Read more
Choosing an image format — Why the same photograph can be 40 KB or 4 MB depending on a single dropdown, and how to choose deliberately.