IDEAS ON IMAGE LIST/SEQUENCE (long term):
v2.0.0	CODE: use the image_layer_struct and allow for complex RGB compositing
each layer is related to a layer inside an image sequence
there may be different sequences for each layer
for each layer, should be displayed: layer name, originating sequence and layer, hi and lo scales, auto level (max range and dynamic range), a list of images with { image name, registration data, selected, FWHM, reference image }
for each displayed frame should be displayed: originating image, registration data, selection status in sequence, FWHM on registration selection, is reference image