When I look at the open hard drive I have loads of folders named differently, e.g. Italy 2006, and there are lots of individual photos that just have the usual numerical file name. Amongst all these photos and within all these folders are anything from two to six copies of the same photo! I need a way to search out all these duplicate photos so I can delete them. I want to keep my photos on an external hard drive for safety but don't want them in such a mess. If I use iPhoto or Picasa or something then don't I have to move the photos on to my Mac? I want the photos all ordered neatly on an ex hard drive with each photo renamed so that it tells me what the photo is of but there are so many I'm drowning! Any ideas?
There are lots of apps that will help you find duplicate files. Search on MacUpdate
NO, using iPhoto does not mean moving the photos to your internal drive. I'm not sure about Picasa, but I reckon it can probably work that way too.
I want the photos all ordered neatly on an ex hard drive with each photo renamed so that it tells me what the photo is
If you want that, then use the Finder, as you are doing. If you want to use a Photo Manager then how things are arranged on the Hard Drive doesn't matter, you do everything in the iPhoto Window. It's a much better way to work, has many more organising possibilities. Perhaps you should view the basic tutorials and see if iPhoto is for you.