How transparency works
Each pixel can carry an opacity value alongside its color. A value of fully opaque paints normally, fully transparent leaves whatever is underneath visible, and the range between gives soft, anti-aliased edges.
That in-between range is what makes cutout photos look natural. Hair, shadows, and curved borders blend into their new surroundings instead of showing a hard rectangular boundary. Editing tools preview that blend live, so a cutout can be checked against light and dark backgrounds before export.
Which formats keep transparency
PNG, static WebP, GIF, and TIFF can all carry transparency, with PNG and WebP offering smooth alpha values. JPEG cannot, because the format has no channel for opacity.
Converting a transparent image to JPEG therefore requires a decision. Most tools flatten it against white or another solid color, and the transparent region becomes ordinary pixels.
- PNG: full alpha with lossless storage
- Static WebP: alpha with smaller files
- GIF: only fully on or fully off transparency
- JPEG: no transparency support at all
Transparency when converting
Filekind keeps transparency intact when moving between PNG and static WebP, since both store an alpha channel. Converting to JPEG flattens it, and transparent areas are filled with white.
The compressor behaves the same way: PNG input becomes JPEG output, so keep a PNG copy whenever the transparent background matters. Checking the result on a busy background is the quickest way to spot a flattened export.