timjohnrose

It’s due to the “-moz-box-sizing: border-box;” declaration at the start of the style.css stylesheet in Twenty-Thirteen, so this will occur in any template that used this rule for the * selector.

* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}

To fix:

just add the following rule after the * rule to display the thumbnails properly in Firefox.:

.thumbholder {-moz-box-sizing:content-box;}

OK, on testing I’ve found it is just Twenty-thirteen, so no drama.

I really want to use this plugin but the thumbnails aren’t displaying in Firefox (I’m using FF 26.0) even on you own demo page:

https://c-pr.es/satellite/examples/simple-satellite/

So it’s not likely a template issue?