Why does my PNG turn white behind the transparent areas instead of staying see-through?

JPEG has no alpha channel at all, so there’s no way to store transparency in the output. The converter fills the canvas white before drawing the image, which is a standard, predictable choice rather than leaving the result undefined.

Can I keep a record of which areas used to be transparent?

Not from the JPG itself — once transparent pixels are flattened onto white and encoded, that information isn’t recoverable. Keep the original PNG if you might need the transparency again later.

Why would a PNG sometimes already be smaller than the JPG version?

Simple graphics with large flat color areas — icons, basic logos, screenshots with mostly solid backgrounds — can compress very efficiently under PNG’s lossless scheme, sometimes more efficiently than JPEG handles the same content. Size gains from converting aren’t guaranteed for every image type.

Is converting to JPG a good idea for a logo or screenshot with text?

Generally not. JPEG’s block-based compression tends to blur sharp edges and fine text, and flattening transparency onto white can look wrong if the logo was designed for other backgrounds. PNG or WebP usually serve graphics like these better.

Does the PNG ever get uploaded during conversion?

No. Everything — decoding, the white flatten step, and JPEG encoding — happens locally in your browser.

Illustration of a PNG image card transforming into a JPG download inside a browser

Image guides

How to Convert PNG to JPG in Your Browser

PNG stores every pixel losslessly and can include transparency; JPG can’t do either. This guide explains what actually happens during that trade — how the alpha channel gets flattened, why the file size often drops, and when PNG is worth keeping instead.

Ready to try the tool this guide describes?

Open PNG to JPG →

How PNG becomes JPG

The browser decodes the PNG into a full grid of pixel values, restoring the alpha channel exactly if the file has one — PNG’s compression is lossless, so nothing about the original pixel data is approximated at this step.
Because JPEG has no alpha channel, the canvas is filled with white first, then the decoded PNG is drawn on top — transparent and semi-transparent pixels blend into that white fill rather than staying see-through.
The flattened, fully opaque pixel grid is then encoded as JPEG using the browser’s encoder at your chosen quality setting, which is where the lossy compression is actually applied.

What changes when you convert

Transparency is the change you’ll notice first: any transparent or semi-transparent area is permanently flattened onto white before encoding. There’s no option to pick a different background color, and once the JPG is written, there’s no way to recover which pixels used to be transparent.

File size usually drops, sometimes a lot, because JPEG’s lossy compression is generally more aggressive than PNG’s lossless approach — but for simple graphics with large flat color areas, PNG can occasionally already be the smaller file, so the direction of the change depends on the image.

This is also the first lossy step in the image’s history if it started as a PNG. Raising the JPEG quality slider (50–100%, default 90%) keeps more visual detail, but at 100% you’re still applying JPEG-style compression that a pure PNG workflow never introduces.

When JPG is the right choice — and when it isn’t

JPG makes sense once you’re done editing and need a compact file for sharing, uploading, or emailing a photo that doesn’t rely on transparency — most photographic content compresses well this way with little visible loss at a reasonably high quality setting.

It’s the wrong move for logos, icons, screenshots with sharp text, or any graphic where transparency or pixel-perfect edges matter — flattening those onto white, or recompressing sharp edges with JPEG’s block-based codec, tends to look noticeably worse than keeping PNG. In those cases, staying with PNG or converting to WebP, which supports both compression and alpha, usually serves better.

Limitations and privacy

The white flatten step isn’t configurable in this tool — if you need a different background behind transparent areas, you’d need to flatten it in an image editor before converting. The file is validated against a real PNG signature first, so a renamed or corrupted file fails safely rather than producing a broken JPG.

Conversion runs entirely in your browser: decoding, flattening, and JPEG encoding all happen locally, and the PNG is never uploaded to a Looty Tools server.

Convert PNG to JPG FAQ

Why does my PNG turn white behind the transparent areas instead of staying see-through?: JPEG has no alpha channel at all, so there’s no way to store transparency in the output. The converter fills the canvas white before drawing the image, which is a standard, predictable choice rather than leaving the result undefined.
Can I keep a record of which areas used to be transparent?: Not from the JPG itself — once transparent pixels are flattened onto white and encoded, that information isn’t recoverable. Keep the original PNG if you might need the transparency again later.
Why would a PNG sometimes already be smaller than the JPG version?: Simple graphics with large flat color areas — icons, basic logos, screenshots with mostly solid backgrounds — can compress very efficiently under PNG’s lossless scheme, sometimes more efficiently than JPEG handles the same content. Size gains from converting aren’t guaranteed for every image type.
Is converting to JPG a good idea for a logo or screenshot with text?: Generally not. JPEG’s block-based compression tends to blur sharp edges and fine text, and flattening transparency onto white can look wrong if the logo was designed for other backgrounds. PNG or WebP usually serve graphics like these better.
Does the PNG ever get uploaded during conversion?: No. Everything — decoding, the white flatten step, and JPEG encoding — happens locally in your browser.

Related guides

Open the tool

Jump into PNG to JPG when you are ready to process your files.

Open PNG to JPG →

← Back to all guides