As Keszler said You need to set the canvas' scrollregion to the size of the image (plus anything else on the canvas).

You will probably need this trick eventually for resizing the canvas's scrollregion.

$canvas->configure(-scrollregion=> [$canvas->bbox('all')] );
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After you add things to the canvas, you reset the scrollregion to the bbox ( bounding box) for 'all' items. Works great.