I have cracked the screen (well, my son did but...) and the only thing happening now is the bottom half of the screen flickers. I have pictures on it that I desperately need to retrieve, nothing happens when I plug the phone into the computer. :-(
If you have a lock code on it, you need to unlock it first. Which means fixing the screen.
If the pictures were saved on the SD card you can remove the card. In the future make sure you make backups of your phone storage to a computer regularly. 90% of issues we see on here won't be issues if files were backed up.