Originally, I thought this was a Basic (FREE) list , but when I look in PHOTOS I see that Image storage is nearly 5.6 GB, well over the 1 GB maximum for a Basic (or Free) list.
Using 5.3 GB for attachments storage
This list is well worth subsidizing at the Premium level ($220/year) however the image storage is halfway to the next storage threshhold of 10GB.
Above that, the list will have to be upgraded to Enterprise at $2200/year.
It appears that the Attachments image storage could become a problem very soon.