BMP
The uncompressed classic of Windows.
Where it came from
BMP (Bitmap) shipped with Windows 3.0 in 1990 as the Device-Independent Bitmap, letting apps draw without knowing the screen hardware. It was simple: a header, then raw pixels bottom-to-top.
Its lack of compression made it the reliable interchange format of early Windows — but also meant a modest photo ballooned to megabytes. PNG and JPEG quickly took its crown.
How it works
A BMP is essentially a header (width, height, bit depth) followed by uncompressed pixel data. No entropy coding, so decoding is trivial and instant.
That simplicity is why BMPs still appear in legacy systems and icons. UWC converts BMP → PNG/JPEG server-side, shrinking the file without loss of visible quality.