If the Linux OS data pointing to the file locations is gone, you will most likely need forensic software to attempt to recover the images. The problem is in the way files are written to the disk. I'm not a Linux expert, but with Windows file systems, parts of the file are written to different parts of the disk and the file system tracks were these file pieces are at in order to pull the data and reconstruct the files when you ask for it. If the Linux OS you are using writes the data to contiguous sectors on the drive, then it would be pretty straight forward to carve the data from unallocated space and recover the files. However, I suspect that Linux puts pieces of the files all over the drive and without the OS knowing where that data is, recovery of complete files is going to be difficult. Hence, the need for forensic software to possibly recover the data. What makes the RescuePro software effective is that data on memory cards is written to contiguous sectors so all you need to know is the header and footer for the file type to recover "deleted" data from that kind of media.
My recommendation would be to limit access to the Linux system and see if you can find someone who specializes in data recovery to give you an estimate on recovering the data. Any access to the drive makes changes and is likely overwriting data that you're trying to recover. I would not attach the drive to a Windows computer unless you really know what you're doing since you could cause more problems than you hope to solve.
All that said, I'm curious whether you were doing a copy and paste or a move of the data? A copy and paste operation, even if it fails, should leave the original data intact unless there is an underlying problem to the Linux file system.