How could I alter the composition so that when column or row count is increased, that the image structure repeats and fills up the additional grid items?
You could use the Append Lists node to append the list to itself, then feed that to Arrange Layers in Grid (composition attached).
RepeatImages.vuo (3.04 KB)
Old Post but meanwhile @vjsatoshi also released a custom node “Repeat List X times” which I thought could be useful too for this.