How to use
- Open bars-32x16.jpg.
- Expect a 32 by 16 PNG.
- Do not expect the PNG to restore detail the JPEG discarded.
Formula / how it works
bars-32x16.jpg becomes a 32 by 16 PNG. The JPEG was lossy already. This step does not invent the detail the JPEG threw away. It only stores the decoded pixels in a PNG so a later edit does not add another JPEG generation. There is no transparency to recover. JPEG never stored an alpha channel, so the PNG is opaque.
The grid does not change. A 32 by 16 icon stays 32 by 16. Quality is not a field, because PNG is lossless relative to the pixels the browser decoded. Two runs of the same bars produce the same size of PNG in this check.
Use PNG to JPG when you are going the other way and you can accept white where a pixel was transparent. Use this page when a JPEG must become a PNG for a tool that refuses JPEG.
bars-32x16.jpg decodes to a 32 by 16 PNG. The JPEG generation that already happened is not undone. There is no quality slider because the PNG stores those decoded pixels. There is no alpha to recover. A second run of the same bars matches the first. A large photograph will not get smaller on this page. It will only stop accumulating JPEG blocks if your next edit stays in PNG. The other direction, PNG to JPG, is where white replaces a transparent pixel.
Open the PNG and check 32 by 16 before you delete the JPEG. The conversion did not enlarge the icon and it did not invent a transparent pixel. If the JPEG was already blurry, the PNG is blurry in the same places. That is the honest limit. Use this when the next tool rejects JPEG. Use PNG to JPG when you are going back and you have decided white is acceptable for any hole. These bars have no hole.
The PNG of the bars JPEG is 32 by 16 and opaque. Nothing transparent was hiding in the JPEG, so nothing transparent appears. Blur that was already in the JPEG is still blur. This page is a container change. It is the right step before an editor that refuses JPEG, and the wrong step if you hoped to sharpen a bad photo. Two runs match. The grid does not grow. PNG to JPG is the return path, and that path is the one that paints holes white.
Keep the JPEG until you have opened the PNG and seen 32 by 16. Deleting the JPEG first is how a blurry decode becomes the only copy. This page will make another PNG the same way if you still have the JPEG. It cannot sharpen. It cannot add a hole. It can stop the next save from being JPEG again. Open the PNG before you delete the JPEG.
The other direction is PNG to JPG. A WebP source uses WebP to PNG.
Worked examples
Bars JPEG at the first run
Inputs: j2n-f: bars-32x16.jpg
On this page, take bars-32x16.jpg and press Convert. The PNG cannot invent JPEG detail that is already gone.
Result: JPG to PNG: 32×16. 0.1 KB
Bars JPEG at the second run
Inputs: j2n-f: bars-32x16.jpg
On this page, take bars-32x16.jpg and press Convert. The PNG cannot invent JPEG detail that is already gone.
Result: JPG to PNG: 32×16. 0.1 KB
Use cases
- Stopping a second JPEG generation before an edit.
- Handing a PNG-only tool the decoded bars.
- Keeping the 32 by 16 grid.
- Accepting an opaque PNG because JPEG had no alpha.
Tips & limitations
- There is no quality slider. PNG is lossless relative to the decoded pixels.
- Transparency cannot be recovered.
- Two runs of these bars match in size.
- The left half stays the red side.
FAQ
What size is the PNG of the bars JPEG?
32 by 16, the same grid as bars-32x16.jpg.
Does this restore lost JPEG detail?
No. It stores the pixels the browser decoded.
Why is there no quality field?
PNG does not take a JPEG-style quality for this button.
Can the PNG be transparent?
Not from a JPEG. There was no alpha channel to keep.
Is the file uploaded?
No. The canvas is in this tab.
When would I go the other way?
When a form wants JPEG and I can accept white in place of transparency. That is the PNG to JPG page.
32 by 16 is bars-32x16.jpg decoded to PNG. A large photo will not shrink on this page.