Reliable Penguin

Create a file at /etc/httpd/conf.d/deflate.conf with the following contents:

SetOutputFilter DEFLATE

# Don't compress picture files
SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ \ no-gzip dont-vary

# Don't compress compressed files
SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ \no-gzip dont-vary

# Don't compress pdf's
SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary