The pic saves as .png.jpg (at least in Firefox) when you save it directly, but saves as .png when you right click and choose Save As. Both are identical in size. So which is it? The pic already has a lot of jpeg artifacts so it's hard to say.

Mordon said:

The pic saves as .png.jpg (at least in Firefox) when you save it directly, but saves as .png when you right click and choose Save As. Both are identical in size. So which is it? The pic already has a lot of jpeg artifacts so it's hard to say.

It's a JPEG with improper extension.