Oomis,
Aside from the lack of modesty (their standards, not mine) of a woman appearing in a photo, there’s a lack of modesty in a man seeing a photo of a woman (again, their standards, not mine).
Since I don’t personally see any photo of a woman being intrinsically immodest, I actually suspect that an editorial policy of not printing pictures of a woman is not due to the inherent immodesty, rather as a precaution that a mistake not be made and a picture be published should not have been.
If I ran a chareidi paper, I would not publish pictures of women, but not because of the inherent immodesty. I would be afraid that a sponsor would want to advertise with a picture of a woman, for example if a couple was being honored, and the picture would not fit my standards. If I refused to publish it, those donors could easily get insulted. If the policy is to not allow any pictures, then there would be no insult.