On a SharePoint Web Front End you can turn on the BLOB cache which allows the webserver to cache certain file types on the front end without having to go back to the SQL server.
The setting for doing this is in the web.config file of the web application. For example to activate it on the cp Portal I used the following configuration:
<BlobCache location="C:\BlobCache\14" path="\.(gif|jpg|jpeg|jpe|jfif|bmp|dib|tif|tiff|ico|png|wdp|hdp|css|js|asf|avi|flv|m4v|mov|mp3|mp4|mpeg|mpg|rm|rmvb|wma|wmv)$" maxSize="10" enabled="true" />
The line was already in the web.config file but I had to change enabled to “true” and also create the folder c:\BlobCache
The users also have to be changed a la: http://technet.microsoft.com/en-us/library/ff758656.aspx