It’s usually not the pictures of people that deter me from anything. I’m a woman of mixed race/ethnicity (middle eastern/latino) so I have basically given up hope that I will find someone who remotely looks like me in the stock photos on career pages :-/ As such, photos do not factor into my decision to proceed — I am not going to “fit in” in no matter what I do, and I have learned to be okay with being the first or the only minority and/or woman in a place.
Usually it’s the cliched language that gets to me most. There are startups out there that don’t have people with real management training at the helm and for me that kind of language (ninja! hero! guru!) is a giveaway that the culture is one I should run from. It means that they can’t promise me an environment devoid of groupthink, personality worship, and excessive demands on my time and resources (for example: expecting me to use work email on my phone but not providing compensation for that). I have an MBA too and I usually lose patience with things like this pretty much immediately.