I didn't realise you could optimise the search for just photos.
Well, if you don't look for 'files' and you narrow the search down to 'photos', you've theoretically made it easier for yourself for a number of reasons... you have a greater knowledge of what file formats to scan for, including compression and storage algorythms, etc... you don't need to recover a complete file if you know the image component is fine... it's easier to reconstruct images than it is misc files... basically you can create more specialised code for the search.