ImageWell is to indicate to your user that this area is editable by them.
Display images and accept drops in ImageWell when it’s an image your user is supplying.
If it’s just to show an image on the interface, yes use a Canvas + Background
SVG’s have VERY little OS level support
They’re oddly found in lots of places but not well supported by the various OSes
Most support you find is “one off” in specific apps, browsers etc