currently this is set globally at /admin.php?ctrl=display
Wouldn't it make sense to allow Collection Skin settings to override this?
If for example Bubble tips is set to allow globally then the thumb size should be configurable by skin settings. Currently there is no way for the skin settings to have an impact here.

if( is_admin_page() )
			{	// Set avatar size for Back-office
				$avatar_size = $Settings->get('bubbletip_size_admin');
			}
			else if( is_logged_in() )
			{	// Set avatar size for logged in users in the Front-office
				$avatar_size = $Settings->get('bubbletip_size_front');
			}
			else
			{	// Set avatar size for Anonymous users
				$avatar_size = $Settings->get('bubbletip_size_anonymous'); // <---- Skin Settings?
				$avatar_overlay_text = $Settings->get('bubbletip_overlay'); // <---- Skin Settings?
				$link_class = 'overlay_link';
			}