Here's a bit of a test
It looks broken. Can anyone else see it?
Edit: this is what I tried. Maybe it will get the ball rolling and someone else will add some missing info to get it working.
In DropBox I turned on Camera Upload so it accesses my photo album and uploads it to a folder on their server. Then, in Dropbox, I navigate to the camera upload folder and select the image I want to post. Using the iOS send to icon (the square with the arrow jumping out) I selected copy link and pasted it into the IMG tag above. But it's broken. Like when you try and get Facebook image.
Does anyone know how to move an image from the Camera Upload folder in DropBox to the Public folder with the iPad. Links to that folder definitely work.