I just got my 302, updated to 15.2 and added the webkit browser.
I tested you manga link, it works the main problem is that there seams to be no way to center the actual manga, so it's very "fiddely" to see the actual manga. (need to scroll left /up/down/)
but the image shows up
It might be there is a way to do see this better , but I even cannot get to the menu (like told when you start the browser.app)