SUMMARY
I have a lot of photos on my smartphone and from time to time I import them into my photos folder. The problem is that I don't delete the photos on my smartphone afterwards and therefore I have next time to search through all photos and checking if they are already sorted or not.

The idea would be to import all photos into a single folder "smartphone" and then using digikam to find all duplicates and deleting all photos from this folder which have already duplicates in one of the other folders.

Therefore it would be nice if it is possible to search for duplicates and everytime a duplicate is found the other not in the "smartphone" folder is the reference to delete the duplicates quite easily.