A gallery can sometimes be a good test for if the game is worth it, not so much to see the content but to see how much it is. When a game is promised to be "hours long" and then only has 5 pictures? The gallery is a nice way for me to know whether I will be reading text or watching scenes.
I skip the dialogue if the translation is poor. I also sometimes do it if it is a scene for a fetish that I am just not into, so I prefer to pass it quickly.
animated is preferred, but I guess there is nuance to the art style, and if (in the case of a game) they only have one animation in many images making it stick out. Then I could prefer if the whole thing was not animated just for consistency.
I prefer some basic story. But also for me I prefer what I get to match the description given. When told an "epic story" just for a gallery viewer, I feel rather disappointed.