Sites now not displaying images

I installed W3 Total Cache to a subsite on my server. I activated the plugin and ran it. After that everything I have had problems with images. For example, the screenshot.png file isn’t showing in the theme preview.

Unfortunately, this affected all of the sites on my server. A good example of an affected site is: trustit.pro.

Please – can anyone help me to fix this issue?

http://wordpress.org/extend/plugins/w3-total-cache/