Posting images here, or anywhere on the internet where you are not receiving monies would be, as I understand it -- I'm not a lawyer, considered personal use. So as long as the license for the models/props/etc doesn't restrict from using their item for personal use (I've only heard of restrictions like this once, most people are fine with this) you are in the clear.

BTW, whether they ask you to in the readme or not, it's always a good idea to give credit where credit is due.