They look like they have been copied from the pages of a book,
where the ink bleeds into dark areas. Original, untouched
actual photos would be best, IMO. Simply scanned,
they should look ok - even with the white specs.
The watermark is a good idea.........
I will in the future put up both untouched and touched photo's. I find the touched up photo's make it easier to see details. I don't have the original untouched photo's on my computer but I did check the photo's themselves. They both have different types of paper and sizes. One is passbook size with no printing on the reverse and the other is a small snapshot taken at home I guess and is marked several times with Agfa Lupex with two lines underneath. I haven't done the UV test yet.