LittleStain Many thanks!
For anyone who finds this thread, here's what the manual says:
"Load image from URL
Load an image from a given URL. The current animation frame will be replaced with the image. It is not shown until the image has finished downloading, and On image URL loaded triggers. Images loaded from different domains are subject to the same cross-domain restrictions as AJAX requests - for more information see the section on cross-domain in the AJAX object. Data URIs can also be passed as an image, e.g. from a canvas snapshot or webcam image. The Size parameter sets whether the Sprite object will be set to the image size when it loads, or whether to keep its current size and stretch the image."