Are you certain that the images were on the card on not on the device? I ask because showing in your gallery doesn't mean they are on the card. It can show both. I would definitely check the device.
Also, when you took the card out, did you put it into something else (as in another device)?
One more query... could someone have deleted them on you?
If none of the above applies, or you have checked those places and the pics are still missing, then I would suggest trying one of the following. First, you can try hooking the card up to a computer and seeing if you can see the missing images through there. Sometimes they will show on one device and not another.
Second, there are actually a few apps/programs out there that "may" be able...