Not sure what you mean; You can open the image "inside Emacs" just like any other file, just Cx Cf to find it, and Cc Cc to switch the rendering of the bitmap.
According to the code, it looks like this:
(defimage test-image ((:file "~/Pictures/greenbug.xpm"))) (insert-image test-image)
Or even easier
(insert-image (create-image "~/Pictures/greenbug.xpm"))
source share