Are you wanting the user image? or the image of the beer that is being shown at that moment in the code rendering?
Been awhile since I’ve looked at the plugin or the response coming from the Untappd API, but I did add the following filter:
$user_markup = apply_filters( 'untappd_user_markup', '', $brew_data );
Essentially I let a user define all their own custom markup, and if they return anything, it gets rendered. If the $user_markup
variable is an empty string, then I render my default markup. The $brew_data array variable will hold some custom html classes to use on the markup, as well as the checkins list. The checkins should be decoded JSON, as I take care of that before saving the transients.
Hope that gives you some ideas of how to proceed.