




 
The function write-external-image writes an external image to 
destination
. If 
destination
 is a stream, it must be an output stream with element type compatible with (unsigned-byte 8), that is one of cl:base-char, (signed-byte 8) and (unsigned-byte 8). If 
destination
 is a pathname or namestring the file is opened for output with the correct element type, and write-external-image writes the bytes to the resulting stream as if by cl:write-sequence.
if-exists
 is passed to open when opening 
file
. The default value of 
if-exists
 is :error.
CAPI User Guide and Reference Manual (Windows version) - 25 Feb 2015