Yes, you would need to increase the output size.
You can access at 1,3,1000,1000 image by using an indexing operation
image0 = output[0,:,:,:]
image1 = output[1,:,:,:]
...

Saving the images can also be done in this way (a sketch)
for i in range(8):
    curr_image = output[i,:,:,:]
    save_image(curr_image, i,)
    ....