Alpha Maps using Maya 2016

Hello, I am trying to get alpha maps to appear in the Maya 2016 editor. I am using .JPG and .RGB. If I use a lambert type on a plane with the rgb as transparency it’ll show like this:

If I render it, it’ll look like this: (Put a red background behind the shadow to show what it’s supposed to look like) Screenshot_106
I’ve gone through a few videos but none seem to work the way I want it to. Any ideas?