When you generate a public link to an image file living in your Dropbox, it generates now a link to a viewing page.

Even if that can be handy when you want to share your last vacation pictures with the rest of your family, this link is not compatible with including a direct link to these images in a blog post or in a web site, using a ![] tag in markdown or an IMG tag in html.

Fortunately, there is a solution to this problem (at least with the current functionning of Dropbox, and I hope that Dropbox will not completely block direct linking in the future):

You should add ?dl=1 at the end of the image URL, without separating it with a space from the URL given by Dropbox.

If the initial URL was, for example, https://photos4.dropbox.com/gjyhihdyd/image.png

you must replace it with:

https://photos4.dropbox.com/gjyhihdyd/image.png?dl=1

That should give you an embeddeble image.