Kids don’t raise a red flag with me. I think pictures with kids are sweet, providing they’re not obviously posed. A guy I knew was -very- protective of his niece and loved her to bits; he was an only child and I can easily picture him posing with her. A candid, genuine shot with a kid, if anything, would make me smile.
The only red flags are obvious crap pics like underwear shots and posing with “conquests”. (If you’re so damned hot, why aren’t you dating your little trophies instead of going to an online dating site?)
Yellow flags would include party pictures, not because they’re creepy, but because it might signify that his interests are different than mine.