The Seme takes this photo to send the Uke. But we don't see pic. http://www.mangago.me/home/photo/1291607/
http://www.mangago.me/read-manga/19_days/
Oh I just remembered two:
http://www.mangago.me/read-manga/renai_rubi_no_tadashii_furikata/
( the second story has a scene where the main guys have some fun with a camera idk if this helps but it's totally hot)
http://www.mangago.me/read-manga/hadakeru_kaibutsu/
(sequel to the above)
http://www.mangago.me/read-manga/ushiro_no_shounen_darling/
(chapter 2 of this has the story I was referring to)
Also http://www.mangago.me/read-manga/okane_ga_nai/ (btw it's not everyone's preference just a bit of a warning it has rape, blackmail etc.)
Just curious lol but is there like any yaoi where the uke/seme sends nudes? Lol