I’ve been using a T-Mobile UK connection through a Nexus One to stay online in Blighty. It turns out that they employ some shenanigans to keep their bandwidth costs down.
A few tricks seem to be happening:
- A transparent proxy loads your requested images, but sends you a more compressed version of your image instead.
- All unnecessary formatting is removed from the page source, i.e. spacing, tabs and so on from the HTML.
Here’s what the compressed image looked like:
Here’s what the original image looked like:
How much bandwidth did this save?
Here’s what we know.
- In my very non-scientific testing, the extra compression seemed to approximately halve the size of the image delivered.
- According to the YUI people, average image pageweight is around 50% due to images.
Therefore, T-Mobile should be saving around 25% on every pageload. This comes at the cost of a slightly diminished user experience for users, maintenance costs for the proxy and script files (albeit minimal), and potential subtle brand damage (a user might perceive T-Mobile delivered internet as worse quality).
Update: You can disable the image compression by visiting http://accelerator.t-mobile.co.uk/ while connected via t-mobile.