I think that many people workflow is to collect sample images (JPGs and PDFs for background, icons etc...) and drag'n'drop to the canvas to rapidly design GUIS or Mockups.
In Photoshop, this operation creates an embedded document (smart layer) with any kind of file; but in APhoto it works only with APHOTO files, PDF and SVG.
I think that it can be not so complicated to convert on-the-fly a PNG or JPG to APHOTO format when dropped, to create an embedded document that can be very useful, instead an image layer, that can be lossless transformed but not reused several times or edited with layers like an embedded doc.
Actually, i must convert any "downloaded" PNG or JPG to APHOTO, before use... not so comfortable!
