This workflow creates a 3x3-montage out of 9 ordered, equisized (X,Y,Channel)-images where Channel is RGB. The first image maps to the upper left corner of the montage, the last image to the lower right corner. Montage creation is done channel-wise, i.e. the image is first split into its different channels. The resulting montages are merged again in the end.
This is a companion discussion topic for the original entry at https://kni.me/w/qeCw-Ac_uGMJ2TQa