What Is a Transparent PNG? (And How to Keep It That Way)
A transparent PNG lets the background show through parts of an image — essential for logos and overlays. Here's how it works and how not to lose it.
How transparency works
A normal image stores red, green, and blue for every pixel. A transparent PNG adds a fourth channel — alpha — that records how see-through each pixel is, usually with 256 levels from fully solid to fully invisible (a 16-bit PNG has 65,536). That’s why a PNG logo can sit cleanly on any colour background, with smooth, soft edges instead of an ugly rectangle.
Why JPG ruins transparency
JPG has no alpha channel at all. The moment you convert a transparent PNG to JPG, every transparent pixel must be filled with a solid colour. Which colour depends on the tool: a browser left to itself fills it with black, while the tools on this site paint white underneath first. There’s no way around it; it’s a fundamental limitation of the format.
If you need transparency, save as a format that keeps it — PNG, WebP or AVIF — not JPG. When you do convert a transparent image to JPG, the converter fills the see-through parts with white, because JPEG has no way to store transparency. There is no setting for a different fill colour.
Keeping transparency intact
To preserve transparency, convert between formats that support it: PNG to PNG, PNG to WebP, or WebP to PNG. Avoid round-tripping through JPG at any point, because once transparency is flattened to a solid colour, it can’t be recovered.
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