Just responding in case any one else is looking for an answer to this, as I was. After 6+ hours or trial and error, I think I found a solution.
This will allow you to link the index thumbnail or index avatar (whatever it is called) to the parent category, rather than to the latest photo's sub-category, when NOT using the forum style layout.
Find this:
Code:
Content visible to verified customers only.
Replace with this:
Code:
Content visible to verified customers only.
AKA, change $pcat to $id.
I have not tested how the change affects other areas of the software. But on main gallery index, and sub album views, it does what I wanted. Hopefully it wont muck something else up.
Also, my 2 cents, this should be an option for the admin in the usercp in future versions. (If not using Forum Style -> Link to newest sub gallery or parent?) etc etc.
Keywords - Thumb Thumbnail Link Index Categories Category Latest Recent Not