K
Ken Blake, MVP
File | Batch Conversion/Rename
or, from the Thumbnails view,
File | Start batch dialog with selected files
Ah, you meant that it was already part of Irfanview! I thought you
meant that it was an additional utility put out by the Irfanview
people, and had to be downloaded from http://www.irfanview.com/
So I already have it, thanks.