My photoarchive is, as you suppose, mainly from scanned slides and is posted at
http://www.railfan.net/railpix/submit/ianroberts
This is a world wide collection from my travels between 1954 and 1998
The South African Locos are spread throught the archive as the intent, in dial up days, was to upload 5 photos per day and this was done to provide more interest for the general user than posting all photos from one country together.
The slides posted to this site have been re-enhanced as my program is now more sophisticated but as Dave pointed out is still capable of further enhancement.