So for the first two, you have to talk to Robin while they're in the living room. Under the "Affection" tab, both scenes will be unlocked from the Progression 1 and Progression 2 options which are "Watch a show with Robin" and "Compliment Robin's outfit"
The last two is when Robins in kitchen. Talk to them and click "Talk to Robin". The progression 3 option will give you one images which is the "Make Robin a special 'milkshake' ". The other picture is from the "Affection" tab, and its the Progression Level 3 option, which is "Fantasise about Robin"
just these ones