Welcome to Android Central! Which phone? "Device Memory" refers to the phone's internal storage, not the SD card, so it's possible the phone itself is faulty.
If you did save your pictures and any other data on the SD card, you could try transferring them to your PC. It wouldn't corrupt your computer unless it was some kind of virus (which, as long as you weren't installing shady apps or tapping indiscriminately on browser popup ads, is unlikely).