How to fix a strange image displaying error on Joomla!

Recently a client asked following question regarding her Joomla! site to us:

She said some of the images are not showing:

For some reason the problem only happens on PC computer but it looks on on Mac.

And after hours of researching, we finally defined that problem:

I think the problem might be not on the site level, but at the Server level.  The main reason is that: the Server is using the image or CSS compression.

The reason is that, apache compressed the images with mod_deflate. This is not compatible with IE.

You should modify the configuration file of apache, disable the lines for compressing images.

The configuration file of apache is totally different based on OS and Configuration tool.

So We could not tell you which file, line or keywords to change, unless we have checked the server's httpd configuration.
The only thing we can sure is that, mod_default caused this problem.