Realty Trac includes properties that are in default and not necessarily foreclosures yet. They list each loan that is in default so if a property has a first and a second, they call it two foreclosure listings. I tried subscribing once to see what it had that I didn't have in the MLS and cancelled after a month.
Almost all lenders go through the local real estate community to list homes as both pre-forclosures and bank owned properties.
Even if you elect to subscribe to their service, they will typically only show photos that are of public record from local mapping programs or tax assessor data since they are not members of the Multiple Listing Service (MLS). In other words, if you are looking for interior photos, I don't think they have them!
I agree with Sally, work with a local Realtor that knows the market.