Online dating is mostly just women trolling for emotional attention.
However, you could use a bit of game to improve your odds. Use this as your opener:
"Hey, i would remove that pic from your profile"
Get her to qualify herself to you rather than the other way around.
I agree you have to insult them in the most subtle of ways dont be too rude but say some slick sh1t and they will. Always come a crawling....