I think guys of all sizes send dick pics. Many seek validation about there size or look one way or another.
Some want to show off, some are just wonering if theirs is "okay", some actually seek humiliation.
I don't send anyone unsolicited pics, but I send mine to those who want to see ito find out f it is liked or not. Is it desirable? Does it turn you on in any way? Is its size to your liking? Is it too skinny?
I couldn't have said it any better. A lot of us like to show off, many seek validation, many like to just share the artistic side of themselves.