> I meet some problem with some site which (at purpose 
I 
> think) change the size of their image to a negative 
> value (-1). I guess Httrack compare the size to 0 
> before downloading the file, which gives an error. 
Is 
> there a mean to overrule that test ?
No - invalid sized generally means errors when 
downloading. But you can try 'tolerent requests', 
which may work in this case?