Add support for opening common images

[arthurmco]

Add support for opening images into raw data.

There's a crate in Rust named image that should do this for us.

Possibly add an ImageFile struct/trait that encapsulates this file object, and an ImageFileOpener to open them.

[arthurmco]

Option is there now, but there's nothing to do with those images yet

Closing this when we do at least small editing with them