The $? problem is mended, still the empty image persists!
gmic version sp ?
[gmic]-0./ Start G’MIC interpreter.
gmic: GREYC’s Magic for Image Computing: command-line interface
(https://gmic.eu)
Version 2.8.4 (pre-release #200207)
Copyright (c) 2008-2020, David Tschumperle / GREYC / CNRS.
(https://www.greyc.fr)
[gmic]-1./ Input sample image ‘waterfall’ (1 image 750x500x1x3). (1 image 0x0x0x0).
[gmic]-2./ Display images [0,1] = ‘waterfall, }’.
[0] = ‘waterfall’:
size = (750,500,1,3) [4394 Kio of floats].
data = (40,58,75,57,70,52,48,58,58,39,45,67,(…),27,22,17,24,24,27,27,27,27,27,28,27).
min = 2, max = 252, mean = 55.7616, std = 52.8027, coords_min = (746,32,0,0), coords_max = (242,179,0,2).
[1] = ‘}’:
size = (0,0,0,0) [0 b of floats].
data = () [float].