Why doesn't WGET work with Cosmote or Wind GR'

[inquisitor]

Have you checked, if faking the user_agent does actually take effect? I just found another syntax for changing the user_agent on Google:

$ wget -U "user agent" http://example.com/

You should first make sure that the user_agent manipulation works for sure. You should download http://pgl.yoyo.org/http/browser-headers.php while connected through wifi and check if the user_agent has actually been changed.

If the user_agent is actually changed and it still doesn't work through the cell network, they seem to perform some deeper inspection of your requests. Maybe the proxy checks in the EIR (a network element of every GSM-network) what type of phone you use and then only accepts the user_agent of that certain phone. Then you should use only the user_agent of the phone, which is registered on the network (the Nokia N70 in your case):

NokiaN70-1/5.0609.2.0.1 Series60/2.8 Profile/MIDP-2.0 Configuration/CLDC-1.1

If that doesn't work either, you should check if you can download that image when you use the native browser of your N70 and/or of the N810. That could help isolating the cause.