Rotated in 90° increments or mirrored into the standard anatomical viewing orientation, centered on a square black (pixel value 0) canvas fit to the radiograph’s long axis, downsampled to 250×250 pixels by picking on nearest pixel from the input image (by Pillow (version 8.4.0)), and stored in 16-bit Tag Image File Format (TIFF) with a greyscale look-up table stretched to display 0 as black and the radiograph’s maximum pixel value as white.