Hi @JoshMercurio,
Can you give us more detail about how you're trying to include the image? Are you using the "attach" button below the rich content editor (text box) or trying to insert the image into the text box itself? The file storage calculations for discussions in Canvas get pretty complex. In general, things attached to graded discussions should be exempt from the quote, but ungraded discussions count against the quota. That small difference is why I'm guessing things might work fine in one discussion for you but not another.
You also mentioned Kaltura, which is a 3rd party add-on which has completely different storage from Canvas, and probably why that worked, albeit with a border around your image.
If you get us a bit more info, we might be able to offer some suggestions or confirm if things are working as intended.
-Chris