Single women receive strange photographs from men through the dating websites that allow attachments and also those that allow them to email each other from their personal accounts (such as Yahoo, Gmail and Outlook). Nudity is acceptable unless it's focused on one's penis, which is very common, unfortunately, but the word "strange" is for ostentatious displays of illegal drugs and grandpa's rifle. No one wants to see it, especially women.
The real question is what were the men thinking when they sent it. They're excited by their toys and they like to show them off, and to them that's all that the marijuana farm is. It's the adult version of "show and tell" from kindergarten.
There may be an audience that would appreciate seeing one's rifle, but not women. Dating strangers is scary enough without knowing about their gun collection, and knowing about it compounds the situation.