Splitting scanned images vertically, halfway across width of image
I've got a batch of about 150 JPEG images that are named 0010.jpg, 0012.jpg, 0014.jpg ...
I am trying to figure out a command that will take each of these images and say "Go 50% across the width of the image from the left edge, and split it down the middle (from top to bottom). This will create two seperate jpg files, one for the left half, one for the right half. If the original (unsplit) image is named 0150.jpg, then the left half would be named 0150.jpg (same as original), and the right image would be named 0151.jpg".
How do I do this? I know I can do this with GIMP by manually editing each image, but that will take many hours to do. I am guessing that there is probably an imagemagick command that I could use to do this very quickly...