Plugin Slowing Site Way Down and Images Loading Slow

When I run my site through gtmetrix.com with the plugin activated I get an “F” rating when I disable the plugin I get an “A” rating. The images are taking too long to load. My website readers are remarking the images are taking too long to load. HTML Rewrite method is the only method that worked — the other option did not.

I am on Genesis Framework with a child theme and use Web Synthesis for hosting.

http://www.healthylivinghowto.com

This is what my site host says:

“Your page size is almost 7.5MB (!!!), and that is really bad. To have an idea, an .mp3 file usually have a 4MB size, so visiting your page is like downloading two songs. The retina plugin seems to be loading the normal image AND the retina one at the same time, causing this.”