Social Icons error

I am getting these errors over and over from site graders on the Social Images that come with the theme for the buttons to social networks.

“The following images served from jawscleans.com should be combined into as few images as possible using CSS sprites.”

https://www.jawscleans.com/wp-content/themes/tempera/images/nivoslider/arrows.png
https://www.jawscleans.com/wp-content/themes/tempera/images/nivoslider/loading.gif
https://www.jawscleans.com/wp-content/themes/tempera/images/socials/Facebook.png
https://www.jawscleans.com/wp-content/themes/tempera/images/socials/GooglePlus.png
https://www.jawscleans.com/wp-content/themes/tempera/images/socials/Instagram.png
https://www.jawscleans.com/wp-content/themes/tempera/images/socials/Pinterest.png
https://www.jawscleans.com/wp-content/themes/tempera/images/socials/Twitter.png

Is there anything I can do about this?

Thank you,
~JET