I use the free program IrfanView
http://www.irfanview.com/ to work with images. It can re-size images for you if you need. When working with these faint images, sometimes it helps to make them smaller.
My husband showed me how to use the photo-manipulation tools. Using the 'negative' function (makes an image look like a film negative would look) -- someone was kind enough to send me a couple of photos of gravestones, and the text which can barely be seen in the regular photo shows up better when you look at the stone as a negative. For other images, the 'edge detection' can be a great help.
If you aren't using IrfanView already, give it a try - and if you are, don't be afraid to fool around with the enhancements. You can always make a copy of your image file and then work on the copy, leaving the original intact.
Jan
