1. A data processing method comprising: receiving a digital image file comprising a plurality of digital channel datasets corresponding to a plurality of image channels, wherein the digital image file includes an image region and a non-image region; determining a boundary for the image region; for each channel in the plurality of channels, generating a buffer region by: using the digital channel datasets, identifying a plurality of pixels along the boundary; for each pixel of the plurality of pixels, copying the pixel one or more times outward into the non-image region in digital memory; and storing a modified digital image file that includes the buffer region.