I'm trying to copy part of a large canvas onto a smaller canvas. I had been doing this by retrieving the image data from the first canvas, at the required location, using "get_image_data" and then writing it to the smaller canvas with "put_image_data", as shown below:

image_data = canvas.get_image_data(x=0, y=0, width=64, height=64)
canvas2 = Canvas(width=64, height=64)   
canvas2.put_image_data( image_data, 0, 0 )

This was working, but now seems to be broken and I'm now getting an error "cannot write mode RGBA as JPEG".

The image loaded onto the first canvas is a PNG, so does have a transparency channel and I can put the image data onto the new canvas if I drop this channel (image_data[:,:,:3]) - but I'd like to keep the transparency.

So, is there another way that I can copy a section from a large canvas to a smaller one, or put image data while retaining the transparency?