The problem is the background image uses a non-standard palette. In your URL, the image is http://ui-cloud.com/wp-content/themes/uicloud/images/body-bg.jpg. If you save that, and view its properties, it was created with Adobe Illustrator CS5. That's a hint that when it was saved, it used the default Adobe RGB palette instead of a web safe standard RGB palette (sRGB).
Unfortunately, browsers will display non-standard palettes differently. IE and FireFox seem to display this image the same as it appears in an image editor, Chrome does not. Using chrome's optional color management switch (--enable-monitor-profile on the chrome start command line) did not help with this problem.
If you have control over the content, there are several threads about using converters to fix the palette incompatibilities, like this one. I used an image editor that converted the palette, and that fixed the Chrome display discrepancy.
But where you aren't able to control the content, I wasn't able to find any easy solution on the google chrome help page. Perhaps someone else will know how to modify how Chrome renders these adobe palettes more consistently.