From experiment I have determined that:
ods graphics / imagename="myname";
Allows only letters, digits, underscore and space in myname. This is much more restrictive than file names, e.g. in ods html5 page="myname".
- Please allow many more characters which are valid in file names.
- Until this is done, please update the documentation to list the valid characters. I had to experiment to discover this.
