LÖVE

So I've been looking into shaders, and I'm still a little unsure of how they work. I'm attempting to create a shader that can take an image and give it a glass effect that's transparent and keeps a tint of the original colors of said image. I've looked into the share a shader thread, but didn't find anything other than one example that I was unable to translate to be used for an image. Any guidance to info for shaders or help to this issue would be very much appreciated. Thanks!

EDIT: I'd also like to say I understand I could just make the texture with alpha already set but from what I understand the shader could also manage this. I'm just more unsure how to get the kind of glossy material look of glass.

This helped me a lot in understanding how shaders work in OpenGL in general and in Love2D in particular:

http://blogs.love2d.org/content/beginners-guide-shaders