Why a Transparent PNG Turns White When Converted to JPG
Understand why JPEG removes transparent areas and how to choose the right background before converting.
A transparent PNG turns white when you convert it to JPG because JPEG does not support transparency. A PNG can store transparent pixels around a logo, icon, or cutout. A JPEG has to replace those invisible pixels with a visible colour. In the Schwapps converter, that background is white.
Transparency is not white
A white-looking square in an editor may be a preview of transparency, often shown as a grey checkerboard. On a web page, transparent pixels let the page’s own background show through. White pixels are actual white colour. Once a JPEG is made, the transparency information is gone, so converting that JPEG back to PNG cannot restore it.
Decide what should sit behind the image
- Keep PNG if the image needs to float over different page colours, such as a logo, product cutout, or icon.
- Use JPEG for a photograph or a finished design that has an intentional solid background. It is commonly smaller, but its compression is lossy.
- If you want a colour other than white behind a transparent image, add that background in an image editor before converting. Match the colour to the place where the image will be used.
- Preview the downloaded result before publishing. Edges that looked clean on a dark background can show a light halo on white.
PNG: logo + transparent pixels
JPEG: logo + visible background colour
JPEG cannot store an alpha channel.The Schwapps image converter accepts PNG, JPEG, and WebP files and exports one of those three formats in your browser. When JPEG is selected, it paints a white canvas before drawing the source image. This is why a transparent PNG produces white where nothing was visible before.
When to use another format
Choose PNG when the transparent edge matters and file size is acceptable. Consider WebP if your publishing system supports it and you need both transparency and a smaller file; still check the result, because quality and compatibility depend on the site where it will be served. Keep the original transparent file as your master, and save a separate flattened JPEG only when the destination needs one.
Format reference: MDN’s image format guide.