On FindPenguins we allow you to upload 10 photos (or 20 photos as a Premium member) into each “Footprint”.
However, as the number of footprints in a trip is not limited, the number of photos you can upload in total is also unlimited, also as a none Premium member.
The reason for a limitation is that we want you to post footprints for various places: For example a footprint on the beach, one at your hotel and one for the national park nearby.