According to the official page, no limit is stated:

Add images, screenshots, videos, tables, and text

You can upload images to insert or use screenshots that you’ve already published to the Steam Community. Insert YouTube videos, create tables, and format your text to whatever suits your guide best.

I have checked one of my guides, and it has over 70 screenshots.

Yea but my screenshots are not showing correctly then...not sure why. If you look, screenshots for #5, at least for me, show as a link. While all the above one show as the actual screenshot linked to the guide.

Could it have something to do with splitting the guide into different sections from the sections or something?

Aha..i think that is it. I got looking at your guide. Yes, you have over 70 screenshots, but you split the guide contents into different parts. Maybe there is a limit on how many screenshots you can have in one part of your guide? Going to try this with my guide by splitting it and seeing if the screenshots show properly afterwards.

Yep figured it out. There is a limit to how many screenshots per content section you have for steam guides. When it fills, you need to make a new content section. I just experimented by putting in part 2 in my guide and boom..the screenshots are now showing. I am thinking it must be not a known limit that is reached by many people. Anyways, using this annoying method, i can bypass the restriction as i need people to see the screenshots as it helps finding the things in the game.

Glad to see you figured it out, I was going to check my guide setup once you replied, but it looks like you have it sorted out

Yea. There is a limit on each section you have on a guide. Never ran into this issue in the past..of course i tended not to use alot of screenshots in my guides most of the time. This one though required me at least to show the spots since they do not appear in the game's mini maps.