BMP is an old, uncompressed image format from Windows. Because it stores every pixel as is, BMP files are very large and many websites, apps and upload forms refuse them. Converting BMP to PNG gives you an exact, lossless copy that keeps transparency.
PNG is lossless, so every pixel is kept exactly, and it supports transparency. That makes it the safe choice for screenshots, logos and graphics. PNG files are larger than JPG or WebP for photographs, so use it when exactness or transparency matters more than size. BMP files rarely carry transparency, so the result looks the same as the original. Converting removes the bulk, and a BMP often shrinks to a small fraction of its size.
PNG is lossless, so there is no quality setting. The pixels are kept as they are. The pixel dimensions follow the original, each file keeps its name with only the extension swapped, and no metadata or watermark is added. Everything runs in your browser, so your images are never uploaded.
Tip: Screenshots and scans saved as BMP are the usual candidates. PNG is the safe pick for them, and WebP makes them smaller still.
Not with PNG. It is lossless, so the pixels are kept exactly as they are.
Most BMP files have no transparency. The few that do keep it when you convert to PNG or WebP, and get a white background in JPG.
BMP stores raw, uncompressed pixel data. A format with compression, such as PNG, JPG or WebP, saves the same picture in a fraction of the space.
Yes. Add them all, convert once and download a single ZIP. Only the extension changes. A file named scan.bmp becomes scan.png.
No. The conversion happens in your browser and the files never leave your device.