Convert bmp to heif
A browser can't do this one — here is what it can do.
Desktop app only
Nothing that runs in a tab can write heif from bmp. This pair is waiting on the desktop build, which hands the job to the real command-line tools.
Browse what does workAbout BMP
Windows Bitmap
Microsoft's bitmap format, which usually stores pixels uncompressed, so files are large for their dimensions. Almost every Windows program can read it. Convert to BMP when an older Windows tool or embedded device only accepts it; convert away from it to save space.
About HEIF
High Efficiency Image File Format
An MPEG container standard (ISO/IEC 23008-12) from 2015 for single images and image sequences. It can hold HEVC, AV1 or other codecs, along with depth maps and bursts. Convert HEIF to JPG or PNG for apps and sites that cannot read it.