I don`t know of one exactly - but
feh will allow you save the photo currently displayed, I use it to create a directory of photos to get printed into real live photos.
To make a slide show
sudo apt-get install feh
r makes it recursive (go through all subdirectories)
feh -rzF -D 5 /path/to/photos
z makes it random
F makes it fullscreen
D 5 sets the time each photo is displayed to 5 seconds (you can change it to what you like)
When you see a photo you like press s and it will save it.
This is not much use if you launch feh from your photos directory as you will end up with 2 copies of the photos you like. Much better to launch it from where you want the new files to be saved and specify the path.
Type to see all the options
Not exactly what you wanted but may be of some use.