-the path inside the WIM image at which to add the file or directory tree. If
-\fIDESTINATION\fR already exists in the WIM image, then an overlay is attempted
-if it is a directory; this feature can be used to add multiple files to an
-existing directory in the WIM image in one command. If \fIDESTINATION\fR does
-not exist in the WIM image, then any prerequisite directories are created as
-needed to add the \fISOURCE\fR at that location.
+the path inside the WIM image at which to add the file or directory tree.
+.PP
+If \fIDESTINATION\fR names an existing directory in the WIM image, then
+\fISOURCE\fR must also name a directory. This causes the contents of the
+\fISOURCE\fR directory to be added to the \fIDESTINATION\fR directory.
+.PP
+If \fIDESTINATION\fR names an existing nondirectory file in the WIM image, then
+\fISOURCE\fR must also name a nondirectory file. By default, this causes the
+\fIDESTINATION\fR file to be replaced with the \fISOURCE\fR file. Or, with
+\fB--no-replace\fR specified, this generates an error.
+.PP
+If \fIDESTINATION\fR does not exist in the WIM image, then any prerequisite
+directories are created as needed to add the \fISOURCE\fR at that location.