I use the image-cropping tools from my iPhone's Photos app on a daily basis, and I've noticed that I accidentally invoke the Notification Center grabber quite a lot while cropping when I attempt to drag down from the top of the image.
BetterPhotoCrop by iOS developer Andreas Henriksson is a new free jailbreak tweak that moves the cropping interface down enough to prevent the Notification Center grabber from being invoked when you drag down from the top of an image to crop it.