Is there an age limit on the pictures that appear in galleries ?

Is there an age limit on the pictures that can appear in a gallery ? I’ve set a gallery to cull images from a group pool (by the way, the fact that groups have to be “open join” rather than “invite only” in order to appear in the drop-down list in settings is not ideal, although fortunately I was able to work around that). So far I’ve made tests with pictures added to my pool from two different accounts, and regardless of the account, I can see that pictures uploaded in October will appear, but not pictures uploaded in, say, August. How come ?

http://wordpress.org/extend/plugins/awesome-flickr-gallery-plugin/