I had the same thing happen to me.
In the end I just started a new game and copied the intro page over, it might have been an issue with the game being converted to Sugarcube, possibly the stylesheet stuff.
23 days ago(+1)
Okay, pictures showing is fairly easy once you know what to do.
So in my example I put the images in like this
[img["FOLDER/ImageName.jpg"]]
So what you'll want is a folder with all the images in, where it says FOLDER, you type in the folder name and where it says ImageName, you type the image name and type (.jpg .png)
The image folder needs to be in the same place as the game's html for the images to show.
(The game is called index because that's how you get it to play on Itch)
Also, they won't show if you're testing the game or clicking play in Twine.
You need to Publish the game first and play the published version