Plug the phone into your computer. When you get the screen on your phone for "Charge Only" or "Mount as Disc Drive", mount as disc.
Your phones memory will show up as something like the F drive and G drive under My Computer...on the Mac they're labeled HTC storage and Untitled. What ever it labeles them as, one is the internal storage card (HTC Storage) the other is the removable SD card (Untitled).
Open these drives and you're pictures will be on one or both depending on how you save them. Probably under "DCM100" or "Media" or something along those lines...sorry, going strictly from memory here. So find the pictures and just drag them to whatever folder on your desktop you want. Then unmount the drives, unplug, done.