Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
mogrify -format png *.bmp
mogrify: length and filesize do not match `ScreenShot00021.bmp' @ error/bmp.c/ReadBMPImage/785.
mogrify: insufficient image data in file `ScreenShot00021.bmp' @ error/bmp.c/ReadBMPImage/914.
I downloaded your file and IM says it is malformed and will not process it. Also please in the future identify your IM version and platform.
identify -verbose 1ScreenShot00021.bmp
identify: length and filesize do not match `1ScreenShot00021.bmp' @ error/bmp.c/ReadBMPImage/799.
identify: insufficient image data in file `1ScreenShot00021.bmp' @ error/bmp.c/ReadBMPImage/930.
ImageMagick's policy is to reject malformed image files to prevent possible security attacks such as denial-of-service or memory buffer overflows, etc.