SVGeezy is in essence, a fallback plugin. It allows you to use SVGs for all your assets, giving you complete resolution independence.
It checks if the browser supports SVGs, if not, changes the src of the image to a .png instead (or whatever you pass in).
The first parameter is a class to tell the code not to check. This may be because you have no fallbacks for certain SVGs.
The second is a filetype, this can be anything you want, just make sure the file path resolves to an image. ie. '/images/logo.svg', will be replaced with '/images/logo.png'.