Hello
I see that some members have pics they've posted, which can be accessed from their profile page (usually via links in "recent" activity, even though the pics could have been posted years ago)

So, despite my search, I could not find a clue on how to add anything except for updating a new profile pic.

Any help re adding pics would be appreciated.
Thanks.

(test image)

I assume that you're referring to screenshots - which can be taken and uploaded via the GT lite client.

The client also allows you to choose image files that are on your PC.

https://www.gametracker.com/downloads/