@morpheus93 As I want to keep full anonymity (I am fooling ad networks), I cannot allow myself to block images from those "anti-fraud" services, but I can at leasts block the ones of the website.
The thread you linked was very helpful. There is basically 2 methods:
First one is to use a cheap proxy to cache most elements (so you don't download it again) with a cheap proxy and then copy the profile to use it with your actual good proxy. The idea is good, but I cannot allow myself to use a cheap proxy if there is "anti-fraud" services as they could quickly flag in some way the profile by caching something you don't want. So this solution is not solid.
The second one was basically the same thing, but instead of going through the trouble of doing profiles, you have some kind of software that reroute the traffic depending on the source website. So important traffic will be routed to a good proxy while useless traffic will be routed to a cheap proxy. But the problem will still persist, as those useless traffic could be "anti-fraud" that will flag your operation and make it fail. So this solution is not solid either.
In conclusion, blocking images from the main website seems the most secure option to save bandwith, but it will not reduce the bandwith enough to make it profitable as the main costs are the ads and third-party images. For example, my website's image only consume 170Kb. So I am not saving much.
I hope there could be some secure way to save significant bandwith.
If not, I guess I'll have to look into services that offers unlimited data, but usually they are spammed and very expensive.