ImageOptim-CLI doc "find" command trick with options name param.

Hi,

I tried to build an compression grunt watch task for a project, but the directory only solution can be slow in big folders. It would be nice if we could use the "find" command trick according to the ImageOptim-CLI doc.

https://github.com/JamieMason/ImageOptim-CLI#optimise-a-filtered-set-of-images

Thanks in advance.