Even fast connections suffer from multiple HTTP request overhead because of network latency and HTTP request processing overhead.
MSIE7 opens no more than 2 connections per domain, Firefox3 – 4-6 connections, Google Chrome – 6 connections.
Let’s suppose that time to first byte is 70ms (typical response time of http://google.com via 1.5 Mbps ADSL connection from Dulles)
If a page view involves loading of 20 images from the same domain, then total overhead in MSIE7 is 20/2*70ms = 700ms. The more images site contains, the more time visitor will have to wait.
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