After getting used to Photoshop's batch tool to crop double-paged book scans in half, I find it tedious to do the same using Irfanview's batch function since these particular scans don't have a consistent width.

It'd be nice if in "Advanced Batch Conversion Settings" You could set crop width and height to be % instead of px. If it's already there, I don't know where to find it.

Thanks for reading!