After "AJAX Set response to binary" you need another action -
AJAX Request URL DrawingCanvas.SavedImageURL
Then wait for AJAX to complete, and only then save to local storage.
And the loading function is also wrong. You need wait for "Get item" to finish, then load the BinaryData into a temporary sprite. Wait again, then paste the sprite onto the canvas..
Use System action "Wait for previous action" to minimize the number of events.