I was reading a My Encounter the other week (not available online) which had an interview with the editor of The Moshiach Times. In it he described how the practice of other religious magazines at the time (1980's) was to not include pictures of women (or girls) of any kind on the cover. The interview goes on to describe how the Lubavitcher Rebbe (who reviewed every issue before publication) insisted on including a picture of a girl on every cover, even if the theme of the cover (like a boy's room) didn't really fit.
I later found (with pictures of the relevant covers, including a before and after of the boy's room) a similar description of the story here of the covers here towards the end of the article, with a different (perhaps complimentary) description of the nature of the objection that had nothing to do with the content of other magazines.
I also notice that magazines like Mishpacha and Ami never include pictures of women, even in the section written by and targeted to women - never a picture of the author or any female subject of the story. In terms of illustrations, Mishpacha will only include an illustration of a girl in its kid's cartoon series, whereas Ami will include illustrations of adult women.
The Nshei Chabad Newsletter seems to have no issue, not only with illustrations, but also with pictures of girls and women, although I have no idea what drives that decision.
In a couple of related observations, I know of a camp in flatbush that would not show Young Avraham because it contained animations of women, and I saw a DVD which re-enacted "The cow that wouldn't work on Shabbos" where there was a scene of a Shabbos meal where the wife of the home was conspicuously absent.
What are the opinions of Poskim (contemporary or otherwise) regarding the propriety of publishing such pictures, and their reasons?
Note: As should hopefully be obvious, this question is only about modest pictures of women or girls. It is assuming that immodest pictures would be a problem.