Hi Troth,
A recent photo gallery upgrade now enables all photos to be viewed in three sizes: Thumb, Medium and Full (or regular)
The picture size you see when you first visit the gallery is Thumb (which is the avatar size).
Clicking on the the Thumb brings up Medium.
Clicking on Medium brings up the Full size.
There are no other options available to us at this time but you never know what the software folks have up their sleeves.
Stay tuned....
Dave George