image problem

iTunes producer is reporting error:

ERROR ITMS-9000: "Images larger than 2000000 pixels are not allowed in books. The following images are too large: /OPS/images/image26.png

Trouble is, I don't know which image it's referring to. None of the images I used in the original Pages document before exporting to ePub have that name.

There are about 50 images and I have no idea which one is causing the problem.

I've gone back to Pages and tried to examine each image to determine file size, but there doesn't seem to be a way of doing this.

Any ideas?