Taking a photo from a certain angle
This is often done so that you won't see a building looming over the pool or the beach.
"Some would argue that's not (wrong). You're not Photoshopping; you're just being clever, but to us, that's still being dishonest, because the person is going to be disappointed," Garfinkel said.

Getting dressed up for picture day
Accessories can make an ordinary hotel room look extra cozy or opulent, so you might see lots of special touches in a photo that won't materialize when you get there.
"The same way a kid in elementary school is going to put on his Sunday best for his picture, you'll see hotel photos with flowers, champagne bottles, laptops set up, and of course when you get to the hotel room, those things aren't going to be there," Garfinkel said.

Zooming in
Caution: Objects photographed in this way may look larger than they appear.
"This is especially common with pools," Garfinkel said. "They show you only part of the pool; they zoom in really, really close ... so that you can't see how small it really is."

Sexy lady phenomenon
Resort marketing materials will often show an attractive woman surveying an invitingly empty pool.
"The reality is, the pool will be covered with screaming kids or there's a raucous pool party going on, but what they want you to think is that it's completely empty except for this one woman who is always very sexy," Garfinkel said. "Marketers for hotels absolutely love this."
More here: 'The sexy lady' and other hotel photo tricks - CNN.com