Show broken image icon in Firefox

[Alfonso Martínez de Lizarrondo]

Using the custom extension ​-moz-force-broken-image-icon it's possible to make Firefox show that there's an image with a broken url while editing.

So it's a matter of adding

img {
	-moz-force-broken-image-icon: 1;
}

to the internal stylesheet (the image must have some dimensions in order to show, but finally it will appear and it will be possible to edit it).

You can compare the current behavior with the new one loading this html:

<p>Pic 1:<img width="100" height="100" src="broken" alt="current"></p>
<p>Pic 2:<img width="100" height="100" src="broken" alt="proposed" style="-moz-force-broken-image-icon: 1;"></p>

(of course I've applied here the style inline to show how it will work)

[Artur Formella]

Fixed with ticket #3289