Update index.coffee

 If a size contains ">" character, e.g. 64>, apply both to size and width. This allows a user to specify e.g. Size: "64>" which will resize the largest size to 64. A better approach would probably be to make sure it ends with > and check for e.g. ^>

When using this plugin, I can create for example a 64 width 2000 height jpg, which will not get shrunk in the current implementation of "size" parameter. I made this change to fix the problem on my end.
Passing e.g. "64>" now resizes the largest side to 64px