The only ima to flp conversion that is potentially possible, is export of disk images or floppy disk images between .ima and .flp files, both a bit outdated formats, but sometimes still used on legacy machines.
Your best option when it comes to conversion of disk image formats, is to use tools like ISOBuster or similar. At the very least, these tools often have tools that can read and recover the raw data from disk image files and save these to generic or exchange formats (ISO).
Updated: January 5, 2024