I manage a large website with a number of pages related to female models. While the photos are not inappropriate, some text on those pages contained keywords that may throw up a red flag to Google.
I removed any questionable text or alternate image tags from those pages, and only the photos remain. The PSA ads are still there. How do I go about getting Google to give those pages another look, so that regular ads will appear? Once upon a time you could simply email Adsense Support, now it seems that Google has made it all but impossible to have a support member contact advertisers directly.
You might try refreshing one of those pages several times over and over, to see if AdSense always display a PSA. If it always display a PSA, then you know its a contextual relevancy problem.
If sometimes it shows paid ads, then you know its a problem with not enough paid ad impressions available.
I wonder if AdSense has a flag that can be set manually to identify sites as being "adult oriented" considering you have a lot of photos of female models, and you used to have a lot of questionable text. That kind of flag would allow advertisers to block their ads from displaying on such sites. If you can get ahold of someone at AdSense, perhaps you could ask them if this is the case.