When you mean post, do you mean to post your webnovel? I personally use a few different sites and believe that you should try to keep your net as wide as you are able, but be careful not to extend yourself too far.
I personally use three different sites (one of them is Tapas). The sites you pick to publish on should be somewhat based on the genre of work you are writing. Tapas has a pretty robust community of everything, but romance and action-fantasy (particularly Isekai works) seem to perform a bit better. LGBT+ works also have a very safe and welcoming home here. I know there are sites dedicated to horror and mystery works. I would recommend you do a few searches around and try to find the sites that fit you best.
For me personally I also use:
- Wattpad (though it's my fourth platform that I update my backlog onto randomly every handful of months. Wattpad is a mixed bag, but romance is also what tends to do best here.)
- Royal Road (Really good place if you want some honest (and a tiny bit ruthless feedback). They only do Isekai fantasies though and anything that's not system based won't do well. there's also no money to be made here, unless people chose to donate.)
- Inkitt (an 18+ plus friendly website that pays some authors nice royalties for their works. Female lead romance is what does well here, especially if its "adult".)
As for pictures inside my novel, I don't use any, except in the character profile index or a map. I personally feel that pictures can be a little distracting in a web novel. Though that is my opinion and some one else might have better advice.
"What do people like in their webnovels?"
This is a very odd question. Are you asking about popular tropes? How to better write for an audience? Or are you asking what will sell the best?
if it's the last one I would heavily recommend rethinking writing a novel. Novel writing is not an easy feat and if you're going into it for the money you are doomed to fail from the start.
Write a story you want to tell.