If the text of a web page is received within a moderate response time, but the embedded images are displayed slowly bit by bit, it could be that the keep-alive option has been disabled at server side or a downgrade to the older HTTP protocol version 1.0 is forced by the web server instead of using the newer HTTP protocol version 1.1. You can check this by selecting the "HTTP Keep-Alive Efficiency" diagram on the result details menu of a test run:

If the rate of the "Successful Recycled Network Connections" is less than 70% - or if only "New Created Network Connections" have been measured, the web server is incorrectly configured and you should try to enable its keep-alive option. After this, you should measure the web server again to check whether it performs better. We recommend that the keep-alive timeout is configured within a range of 7-15 seconds.