Ed! Beware! It's Microsoft product, y'know. You'll convert x pictures and you will need to buy faster version, or download a patch or authenticate on some server..... 
Buber, Yes, I considered this aspect of the software. As it turns out, the power toys applications seem to not be written by MS. (Perhaps explaining their usefulness and the name "Power Toys" as opposed to "Weak (costly, disfunctional,error prone) Bludgeon"!)
Typically, I do most of my home based computing on non-MS based systems (also Do Not read as Apple, Unix) but decided to use MS for this task.
The other recomended products all sounded really good, but in the end I was only interested in bulk resizing.
Regards,
DisocEd