Section background image sizing

I am wondering if there is a recommended method when placing backgrounds within a section and then being able to be viewed with different monitor resolutions. I typically test my webs using 3 different systems which also have 3 different screen resolutions. Each resolution displays those backgrounds with varying heights and widths sometimes cutting off parts or adding white space. I also place most of my images to "cover", but find the same inconsistencies.

I am wondering if placing those background images into a container might be a solution in forcing the different resolutions to display that full image within the container regardless of resolution, especially when using parallax.

Here is my web: http://gravelroads.homesteadcloud.com/

Each image within each section should be displayed as such to show the full band, centered evenly with the exception of a background that is fixed to the entire site and bleeds thru as you scroll down. I am curious as to how it might look to some of you and then any suggestions on how to fix if images are being cut off.