Watch the Video Demo : http://www.youtube.com/watch?v=VAA4PJFSzRA
Does your T-Mobile myTouch 3G Slide android phone have a memory card on it? And your deleted photos and videos are stored on the memory card? If so, you can recover them with Android Data Recovery program, no matter you deleted, formatted or lost them due to other reasons.
Try the free trial version of this HTC myTouch 3G slide recovery software:
http://www.android-data-recovery.com