I am an avid photographer but because I use kubuntu I can't help you
much. My one suggestion which is not "Linux orientated" (or any OS) is
how you download and delete photos from your camera.
The most recommended way (by many photographers - not only me) is to use
a card reader to download photos. There are several reasons for this.
For me the most common reasons are:
1. If one has more than one card it is quicker and less problematic.
Putting cards with photos in and out of the camera should be done
carefully because the "danger" of doing damage to photos on a card
increases. One may leave the camera turned on accidentally etc.
2. One's camera is "free" to continue taking photos and isn't tied down
to downloading.
You mentioned that after copying your photos to the computer you then
delete the old photos from the card. Let me suggest (almost demand) that
you reformat your card and not simply delete. Formatting should ONLY be
done with the camera and NOT with the external reader. This provides you
with two advantages. The card is really clean and no residue of old
photos are left on the card. The card is "configured" for your camera in
the best way possible.
As I said I use other programs on Kubuntu so I cannot advise you there.