Preview small favicons when uploading an SVG

[Jab2870]

Currently, when you upload a png / jpg etc., we see a 16 px preview of the favicon in the scaling algorithm tab.

I understand why, when using an SVG, the scaling tab is unnecessary but it would be helpful to see a 16px preview somewhere.

I mentioned in #320 that it would also be nice to have a dedicated picture for the small favicons

[phbernard]

That's right. I even forgotten this behavior and had to submit an SVG to see it in action :-/

I think this preview will be better served by #323, which I just submitted.

[Jab2870]

Excellent! I look forward to seeing #323 implemented then. Thanks again for creating such an awesome service