2cbf
2cbf is part of the XDS distribution. It converts any image file format that is know to XDS to a miniCBF file. This program is also used by XDSGUI.
For 2cbf to work with the LIB= option, it is mandatory to have a filename like test_123456.xy, i.e. with a 6-digit number and a 2-letter extension. If you want to use LIB= and your filenames do not follow this pattern, just symlink them, and construct the symlinks accordingly.