One thing to be careful with is that the UK location for WebPagetest is running with minimal to no latency (direct connected to high bandwidth data center connectivity). Odds are that for real users on DSL or other connectivity (where 50ms last-mile latency is not unusual) the bottlenecks may move and using an image sprite for a bunch of those images will help.
We're working on making the connectivity in the UK location more like what we have in the US and NZ locations where the connectivity is more in line with a consumer experience.
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One thing to be careful with is that the UK location for WebPagetest is running with minimal to no latency (direct connected to high bandwidth data center connectivity). Odds are that for real users on DSL or other connectivity (where 50ms last-mile latency is not unusual) the bottlenecks may move and using an image sprite for a bunch of those images will help.
We're working on making the connectivity in the UK location more like what we have in the US and NZ locations where the connectivity is more in line with a consumer experience.