Hi, thanks for all the work that goes into making and updating Tails !
I've been wondering for a while if the fact that Tails uses the native resolution couldn't be used to help break one's anonmity ? Different users would have different screen resolutions, and the size of Iceweasel's window would be different too.
In particular, I have a big screen, so I would easily stand out.
Is there anything in Tails that mitigates this issue ?
Indeed. See the example in the section "Fingerprint users based on browser attributes" of Torbutton's design paper for some numbers on how bad this is.
Torbutton has the (enabled by default) option to "[r]esize windows to multiples of 50px during Tor usage". While this greatly improves the situation, it doesn't completely eliminate this threat (search the Torbutton design doc for this option if you want some numbers).