I have a very long canvas (say 200x1800 pixels) that I have put it in a HorizontalScrolableArrangement. It is a graph of data recordings.
It works OK and when I want to save it as an image, I use "canvas1 save as" method. This step also works alright and the image is saved.
But, I am thinking of how to cut the very long canvas (or image) and divide it to three parts, then put the parts above each other; to have a more or less square image.
Whilst the image extension provides a method for chunking an image into pieces, I am still not sure how you expect a combination of these image to become square, from a very long rectangle. You might want to show an example of what you mean....