Hi @Katiesap,
In addition to the option @ryan_corris provided about seeing alt-text in the RCE (which would work while editing things), there are a couple other ways to view alt text. One would be to right click an image and select the "inspect" option. This will open up a developer mode pane where you can see the HTML of the image, including the alt text. If that's a bit too complex, there are also browser extensions that would reveal alt text, and perhaps other accessibility info. I personally use the WAVE extension which I did confirm will show image alt text when the extension is turned on. Either of these options should work in student view.
I hope this extra info might be helpful too.
-Chris