Yes, when you delete photos using the camera or the PC, the photo is not trully deleted, it is only unlisted, until it is overwritten.
This menas that if you don't copy anything else on the memory card or the HD, you may recover tose photos you have just deleted.
The program supports several file formats like FAT 12, FAT 16, FAT 32 and NTFS, so you wouldn't have any problem.
Usually, trial versions only let you see the photos but they don't allow you to recover them. In this case, Asotech Photo Recovery trial verion allows you to recover photos, although it will not offer you all options.
It is very easy to use, you only need to choose the unit you want to recover photos from, and the program will scan it for recently delted files to show you a list. Then, choose the ones you want to recover and enjoy them again.
Some functions disabled in trial version.