17.7.3 Omitting size attributes from images for DocBook
To eliminate width and height attributes from images for DocBook:
; GraphScale = Yes (default) to put out width and height attributes,
If you do not specify any setting for GraphScale, width and height attributes are included.
> 17 Converting to DocBook XML > 17.7 Specifying options for figure elements > 17.7.3 Omitting size attributes from images for DocBook