I’m not sure if you are doing any kind of image compression before uploading images to the CDN. By either starting or improving the compression, you can help speed up page load times and lower your bandwidth cost. That’s a win/win for everyone!
I just uploaded an image that was automatically cropped and resized (so I know there is some processing going on already). The published version of the image is 302kb. I ran that same image through https://compressor.io/ and it compressed it to 53.7kb… or 82% smaller. That’s a huge difference! Think about doing that for every image on Unbounce.
There are tons of tools out there to do this.
You can pay for a pre-packaged product:
http://www.jpegmini.com/server
Or use some libraries. Here is a list that a tool called ImageOptimuses: JpegOptim, jpegrescan, jpegtran, PNGOUT, Zopfli, Pngcrush,AdvPNG, extended OptiPNG, and Gifsicle.