I have created a "zp_meta" table where, each time the image is displayed, I simply update the count.
As soon as the "shani" theme will be completed I share the new functionnalities....
Anything can be managed with that system...so far, I use the "zp_meta" table to store EXIF, the image DATE and I am also working on something like "tags" also stored in that table (in order to simplify the future "search" function)...
Lots of new functionnalities :o) and so few available time... :o(