Is that on Mac?
Than you could try our Drag and Drop functions in the MBS Plugin:
You get a script triggered when something is dropped and you can query all the file paths. Than you can run a script to check each file and create records and import images as needed.
Have you looked into importing a folder (File > ImportRecords > Folder)? This achieves what you want—each image in the folder in a separate record. You would not be able to use drag and drop though, but a little education—or scripting—would surely overcome that.
It would need outside support of OS script that does drop target run the FM script. This may not problem since drag source is also in the OS window (Finder or Explorer) so drag from and drop to both in same application may be good for users. Full sized FileMaker window (Windows only?) disturb seeing drag source.
Thanks for the suggestions. I'll take a look at these and see if I can get something working.