Template:Click
Appearance
[[File:{{{image}}}|{{{width}}}|link={{{link}}}]]
Copied from Wikipedia. Use sparingly.
Usage:
Just don't use it. Ever! Use [[File:someimage.jpg|widthxheightpx|link=link|alt text]] (for example [[File:wikipedia-logo.png|50x60px|link=w:Main Page|Wikipedia]]) instead which makes:
This template has been deprecated in favour of the link= parameter (failing that use an image map).
Actually, this template just uses normal image syntax now.