But cant you only get an Alumni login if you have been previously enrolled by a registered Cisco academy? So im sure using without ever being a registered student is against the licencing.
Getting IOS images legally is virtually impossible as far as I know, im sure the licencing states the IOS should only be used with the original/registered hardware. Its been said Cisco aren't worried about people using IOS images in GNS3, you can talk about configuring GNS3/IOS on the official Cisco forums etc.
edit: licencing states:
Permitted End Users are students, faculty or alumni of Cisco Networking Academy or such other individuals or entities approved in writing by Cisco. Instructors shall not make any copies or duplicates of the Software except as reasonably necessary to exercise the rights granted hereunder. Except to the extent set forth herein, no distribution, marketing or other transfer of the Software is permitted.
Anyway, im going off topic slightly here and im sure the OP isn't too concerned about PT licencing.