so use ImageType just to detect the user has selected a new size,
and use the size of the returned image for the icon pixel size
Change-Id: If101c586bd2f0d83f668637b48ce3d25a0873358
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/99561
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
