Pixel Dock
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Convert PNG to JPG

Turn PNG files into JPGs to shrink them for email and uploads, or go the other way to keep transparency. Everything runs on your machine — the images are never uploaded.

Which way should you convert?

These two formats solve different problems, and picking the wrong one wastes space or ruins an image.

What happens to transparency

JPG cannot store transparency. When a PNG with transparent areas is converted to JPG, those areas have to become a solid colour, and this tool fills them with white — the safest default for documents and printing. Each converted file says when this happened. If keeping transparency matters, convert to PNG or WebP instead.

Why PNG photos are so large

PNG is lossless: it reproduces every pixel perfectly, which is ideal for screenshots, logos, and line art with sharp edges and flat colour. But a photograph has millions of subtly different pixels, and storing each one exactly makes an enormous file. JPG was designed for exactly that case, which is why the same photo is often ten times smaller as a JPG.

Getting a specific file size

If your real target is a size limit rather than a format — "under 2MB", say — converting to JPG and then running the result through compress to an exact size gives you precise control. Converting alone gets you a smaller file, but not a specific number.