When I export a frame to PDF, it includes the drop-shadow that is drawn around the outside of the frame. This means I cannot use the image in a document without manually deleting the frame (when I’m making a document, I want the document’s style to control frames around images).
Also, the export to PDF would be more useful if it omitted the white background and was instead transparent. This way, when I include the images in documents they won’t block out stuff behind them.