It takes more backbone to stand up for your beliefs than to be silent among the crowd. As an old saying goes, “The nail that sticks out gets hammered down.” We are called to be a light on a hill, the salt of the earth, and different from everyone else. I am not advocating confrontation, but one should not show approval toward sin. This is not an either/or situation. The OP doesn’t have to choose between looking at the pictures or calling down hellfire. The OP can satisfy both conscience and grace by politely turning down the offer of viewing the pictures. My further suggestions regarding subsequent actions stem from the observance that many gays portrayed in the media are, at the very least, pushy, especially when faced with those who differ from their view of acceptance. The OP should be prepared for that.
Except that he is. When one shows pictures of an event to another, there is an expectation of sharing the joy of the occasion with that individual, and through that joy, an affirmation of the event. We should not feel joy at seeing the holy institution of marriage turned into the masquerade of sin that it has become. Thus, the gay person is soliciting a particular response by the act. If he was keeping his lifestyle to himself, he would not be seeking to affirm his life through such solicitations.
Why the jump to extreme conclusions? We should not condone their actions, period. We should not support their sin, we should not accept their sin, and we should not sanction it through legal and social institutions. If they want to sin, we can still be kind and charitable to the person, but we do not have see what they do as “normal” or treat it as such.
Honestly, perhaps you should seek therapy.
A baby born from a sinful act is not intrinsically evil. We do not have condone sinful instances of sex to appreciate that God has still brought a new life into the world.
Also, I do not think I am qualified to speak for Jesus specifically. I look at the examples he left, such as the woman caught in adultery. He did not condemn her, but he did not condone further sin.