Depends....
How big is the pile of picture files? a couple of GB or hundreds of GB.
If the pile is relatively small, 2GB thumb drives are usually sold as loss leaders at the big box electronic and office supply stores for around $10-12.
If the pile is larger, then the previous poster's recommendation of an external HD is a good one. Your PC is unlikely to have firewire, so a USB drive would be needed. 200-300GB are routinely on sale at the usual suspect's stores for about $90.
If you can get both the PC and the Mac on a home network, the zero cost solution is to share the files on the PC, go to the Finder on the Mac, select the Go menu, then Connect to Server. The finder should see the share and allow you to open it and copy the files.
If you are new to the Mac, I suggest you buy one of the "Missing Manual" series of books.