What do you call photos of women who are naked that don't reveal the naughty bits?

Solution 1:

I think you are looking for glamour photography. It is also used as a euphemism for erotic photography and until late 20th century, it was referred to as erotic photography.

Glamour photography is a genre of photography in which the subjects, usually female, are portrayed in erotic or exciting ways ranging from fully clothed to nude but in ways that either may conceal or may otherwise not especially draw attention to the subjects nipples and vulva.

[Wikipedia]

Solution 2:

I think risqué / risky is actually the best term.

Straight from French risqué meaning 'a risk, risky' and defined by the OED as

Risky
3. [After F. risqué.] Bordering upon, suggestive of, what is morally objectionable or offensive.

The reason I think this fits so well is the cover of a 'dirty mag' usually remained within the boundaries of decency, you could see no more than you would at a swimming pool or beach, but the pictures inside the magazine had crossed over 'the line' showing everything in full detail (I won't post example photos).

So the cover pictures are risqué while the contents are pornographic. (Or at least so I am led to believe, I only ever read the reviews of sports cars in them).