I noticed the same thing, I didn’t see any documentation changes related to the icon size so I just upped my source icon resolution. Though the new layout of the notice looks like it needs work, just based on the proximity of my icon to the bottom edge.
I would like to add the Same Issue here on (Windows Firefox 44.0) / 26 Jan 2016
My Notification are also showing up in Large Size and the Icons are also showing in Original Size. While befor all Icons were being Automatically resized to fit the Notification. I even tried to resize the Icons to small size, but Still the Notification + Icons are showing up in Large size.
So what is causing this? Did we find any fix to for this issue.