If you took photographs before digital cameras became prevalent, it’s quite possible that you have full slide carousels sitting around. You can scan those slides and create digital images, but it tends to be a time consuming task. I once had the chore of scanning in a full carousel by hand, and I wouldn’t wish that task on anyone.
If you’re planning to scan a whole bunch of slides, it might be worth investing in a slide scanner, like the Slides 2 PC scanner. Ion Audio makes this sub-$100 scanner that digitizes slides automatically at 5 megapixels. Up until recently, dedicated slide scanners have been horribly expensive. Despite the low price, the Slides 2 PC seems like a good little machine and worth the price.