I've seen both the 2nd and 3rd ones a lot (I'm purely a romance player), but the first one, nope, found many other CGs while modding the game that I haven't actually seen in-game (probably planned to be used, so they've been added so long or something), mostly wedding related, similar to the first CG you posted, curious about them though.
2nd CG is for the Wednesday BJ from Anna when you're 5 hearts with her (this is a scene you can switch off in the Starmaker Profile page, as the event happens every wednesday), choose the "I want that ass" or something option (can't remember the exact wording of the option) and you'll get to see that CG and 2 others.
3rd CG is a random event that only happens on Wednesdays when Anna asks you to go to the park with her. You'll see a few CGs of her in the dress, though there is one I haven't seen here of her, where she lifts up her dress for the MC.