In any case, it amounts to mortal sin on his part for posting it whether it is him or not.
If it is mortally sinful alone to look on a woman to lust after her (St. Matthew 5:28, 1 Corinthians 6:9) then it is likewise for a woman to look on a man to lust after him. It is scandalous to present material that might tempt another to sin mortally in this way, and we know what Christ said about scandals:
St. Matthew 18:7: "But he that shall scandalize one of these little ones that believe in me, it were better for him that a millstone should be hanged about his neck, and that he should be drowned in the depth of the sea. Woe to the world because of scandals. For it must needs be that scandals come: but nevertheless woe to that man by whom the scandal cometh."