Hi Caravaccio,
Welcome to the Apple Community.
Apologies I don't know of any software, or if there is any, that would do this task for you.
Here is a method that may work for you:
if all your photo files are .jpg or .jpeg. as is usual,
and
duplicates all have the same filenames
and
the number of photos will not make the task too labour intensive for you.
Re: "how can get rid of all the duplicates"
.
Open a new Finder window, and in the search field. type. .jpg
You should immediately see all the photo files ending in .jpg. appear, listed by file names, with duplicates all together.
(If this doesn't happen ... Use the View menu in the the Finder top menu bar > Sort by > Name
You could work your way down, deleting grouped duplicates en masse as you go.
When you reach the end, and have one copy only of each .jpg, select them all and drag into one new folder.
Do the same with .jpeg files.
(and if needed, with .png or any other files-types)
Also do the same with video files (check the file extensions used) .mov. .mp4. etc.
Hope this will help / work for you :-)