Yep. I have dev mode on as well as verbose error messages. Silverstripe itself isn't throwing an error, the server just can't access the image files, thus the http 500 error. And it isn't images that I'm trying to insert into my theme. Those are all working fine, most likely because they are stored in the images folder within the theme folder.
The trouble I'm having is images stored within the assets folder which are supposed to be available to my client via the cms to insert into the content boxes via the tinyMCE editor.
If you take a look at the image I've attached, you'll see what I'm talking about. If I take a look at the page resources, it shows that each of those images is throwing an http error 500, i.e. they cannot be accessed. I've tried resyncing the image cache with dev/tasks, but that didn't help. I have no idea what else to do.