No one, it was just a phone gallery pic. Most of them say it was a test image because it had 2 variants, BBC and BWC.
I think it's a pretty safe assumption at least, given that they are placed in the gallery in no particular order amongst the chapters and have been there for a chapter and a half now, with no implementation yet.
Of course an alternative theory could be that one version is supposed to be in the game and another is a random test.
But if we assumed the images were going to be in the game, or maybe just the BWC version I see several possibilities of how one comes to view them:
1. Axel shows Lena to taunt her.
2. Axel shows Ian to taunt him.
3. Ivy shows whomever because Axel shared it with her? Not sure why he would but who knows.
4. Cindy shows Lena to taunt her. This seems really out of character, but let's say their catty interactions increase and Axel's involved with them both.
5. Cindy shows Ian to taunt him. Kinda the same deal as 4, but perhaps if Ian becomes a bit too much of a bitch with her she could lash out? Or if he cheats on her.
6. Lena finds it snooping on Axel's phone.
7. Ian finds it snooping on Cindy's phone.
8. The reverse of 6 or 7, although the conditions for those opportunities would seem much more far-fetched.
9. Wade shows it to Ian, say after a bad break up if he confronts Axel and Axel shares it with him in retaliation? Or Cindy does for a similar reason, though I would hope she wouldn't be that malicious towards him.
For the BBC version I only really see Ian sharing Cindy with Jeremy as a likely option and that would also seem to be in the far future still, assuming this came about.