Image annotation
Drop in a screenshot or photo, mark it up, and export a flattened image or an SVG that keeps the annotations editable. The picture is an element in the document like any other, so annotations sit above it, move with the selection tool and survive a round trip through the file format.
Empty drawing canvas.
The image sits on its own locked layer so annotating never moves it by accident. Exported SVG references the
image and keeps every arrow, box and note as vector geometry; exported PNG rasterizes the whole thing at twice
the document resolution.