Mobile phone evolution, respectively, from left to right: Motorola 8900X-2, Nokia 2146 orange 5.1, Nokia 3210, Nokia 3510, Nokia 6210, Ericsson T39, HTC Typhoon. Copied from http://commons.wikimedia.org/wiki/User:Anders Wikimedia Commons
mobile_phone_evolution.jpg
You can use this image freely, without any restrictions, because it was released into Public Domain.
However, it would be nice if the following credits are given:
by Anders K. Larsen, PD