Texting photos on T-mobile using unlocked ATT Phone GlaxayS3, Infuse, Moto Atrix

[AC Question]

My wife needs to be able to text photos with her unlocked AT&T phone on the T-mobile network,

She has three phone to pick from Galaxy S3, Samsung Infuse or the original motorola Atrix.

 

[STARGATE]

If the phone is unlock, I don't see what the problem is. Anyway, I would stick with the better phone, in this case the GS3 might be it.