From the link:
"This means that, in addition to things like paid-for ads in third party space and e-mail/direct marketing, images and text on a gambling operator’s own website (or social media) that are ‘directly connected’ to their gambling products or other services will be considered ‘ads’ by the ASA.
This includes game thumbnails, screenshots and logos as well as the names and descriptions of games".
Game launch buttons and anything on the site is considered as advertising the game so is included.
'This includes content created by affiliates because this is equally covered by the CAP Code and gambling operators are held, at least jointly, responsible for the content created by their affiliates.' taken from ASA site
EDIT -
This is the letter sent to all sites -
Quote
"This relates particularly to freely accessible ads for play-for-free and play-for-money games
and includes all graphics and images displayed on a website or in third party media"