Chances are, yes, if they have not been overwritten (like by taking other pictures using that card in your camera). When files are deleted, or the card reformatted on most cameras, the pics are still there until overwritten - just like on a hard drive. On a hard drive, you can delete the files, reformat the drive, even repartition it and still get the files back with the proper tools. I've done it.
Bottom line: Some of the programs that recover deleted files from hard drives will also support/work with mounted memory cards (like those in a card reader attached to your computer). It's been a while, so I can't point to a particular product, but they do exist. So yes, it's possible. In fact, it's probable. If you haven't used the card since you deleted the pics, I'd be surprised if you couldn't get them back.
Just don't take any more pictures using that card until you try a recovery tool. On some cards you can flip a little write-protect switch to make sure it doesn't happen (which I recommend doing) until then.