- If it is from a file, then it will be returned in `filename_return'.
- filename_return may be NULL; also, NULL may be returned (e.g., if
- it's a screenshot or video capture.)
+ When the callback is called, the image data will have been loaded
+ into the given drawable. Copy `name' if you want to keep it.
+
+ If it is from a file, then the `filename' argument will be the name
+ of the file. It may be NULL. If you want to keep this string, copy it.
+
+ The size and position of the image is in the `geometry' arg.
+ The image will generally have been scaled up to fit the window, but
+ if a loaded file had a different aspect ratio than the window, it
+ will have been centered, and the returned coords will describe that.