In these forums we never recommend 'duplicate file finders', despite what other parts of this web site may say. The risks are just too great.
Putting aside your photo's for a moment, the problem is this. In Windows many files are shared, but many are not. It is quite feasible for one application to utilise a shared Dynamic Link Library file, (.dll), in the Windows folder or Windows\System32 folder, then another application to use it's own .dll file of the same name, stored it it's own folders. A duplicate file finder would find two instances of that .dll file and delete one. If you delete the wrong one you can halt applications like a 'dead strop'. There is no way of telling which applications use these .dll files, so you are taking a leap in the dark in choosing which to delete.
Back to your photos, how would a duplicate file finder analyse the photos? it doesn't 'look at them' with eyes the way we do. All it can do is check for file type, size, name, date created, and so on. So it is possible you have two files, two different photos, with the same file name, same file type, same size, but in different folder locations. So the file finder will tag these as duplicates, you delete one, then you have lost your only photo of some important event.
Or, you can have two files, two photos, that are the same, but their properties are different, eg different file type, different size, different creation date, etc. So the file finder will discount those as not the same.
Sorry, but the only sure way is to catalog these photos yourself, and work through them and delete any that you are sure you have duplicates for.
in your reviews i find that easy duplicate file deleting software is the one you recommend. is this so as there are a few others. I want to use such a program primarily to find photo or image duplicates in windows 7 hp. with no speed issues..