12.8.2 External images

An External Image is an intermediate object. It is a representation of a graphic but is not associated with a port and cannot be used directly for drawing.

An object of type external-image is created by reading an image from a file, or by externalizing an image object, or by copying an existing external-image . Or, if you have the image bitmap data, you can create one directly as in the examples/capi/buttons/button.lisp example.

The external-image contains the bitmap data, potentially compressed. You can copy external-image objects, or write them to file, or compress the data. Transparency Converting an external image

LispWorks CAPI User Guide (Macintosh version) - 14 Jun 2006