Sub Essai
ResizeExternalImageByWidth("/home/didier/tmp4/about.bmp","/home/didier/tmp4/about_1616.bmp",16)
End sub


Sub ResizeExternalImageByWidth(sURLImage,sURLImageResized as String, iWidth as Integer)
   rem open a sdraw hidden document
   Dim mFileProperties(0) As New com.sun.star.beans.PropertyValue
   Dim Proportion as Single
   mFileProperties(0).Name="Hidden"
   mFileProperties(0).Value=True
   oDesktop=createUnoService("com.sun.star.frame.Desktop")
   monDocument = oDesktop.LoadComponentFromURL("private:factory/sdraw","_blank",0,mFileProperties())
   maPage = monDocument.DrawPages(0)
   rem insert in the drawpage the image resized at 1000
   ImageL = monDocument.createInstance("com.sun.star.drawing.GraphicObjectShape")
   ImageL.GraphicURL = ConvertToURL(sURLImage)
   maPage.add(ImageL)
   resizeImageByWidth(ImageL,1000)
   rem resizing the drawpage
   Proportion = ImageL.Size.Height/ImageL.Size.Width
   maPage.Width = 1000
   maPage.Height = ArrondiEntier(1000*Proportion)
   rem set export data
   Dim aFilterData (1) as new com.sun.star.beans.PropertyValue
      aFilterData(0).Name  = "PixelWidth"        '
     aFilterData(0).Value = iWidth
      aFilterData(1).Name  = "PixelHeight"
      aFilterData(1).Value = ArrondiEntier(iWidth*Proportion)
      rem export drawpage
      Export( maPage,sURLImageResized , aFilterData() )
      On error resume Next
      monDocument.Close(True)
      On error goto 0
   End Sub

Function ArrondiEntier(Nombre as Single) as Integer
If Nombre-Int(Nombre) < 0.5 Then
ArrondiEntier = Int(Nombre)
Else
ArrondiEntier = Int(Nombre)+1
Endif
End Function



Sub Export( xObject, sFileUrl As String, aFilterData )
  xExporter = createUnoService( "com.sun.star.drawing.GraphicExportFilter" )
  xExporter.SetSourceDocument( xObject )
  Dim aArgs (2) as new com.sun.star.beans.PropertyValue
  Dim aURL as new com.sun.star.util.URL
   sFileUrl = ConvertToURL(sFileUrl)
  aArgs(0).Name  = "FilterName"
  aArgs(0).Value = "bmp"
  aArgs(1).Name  = "URL"
  aArgs(1).Value = sFileUrl
  aArgs(2).Name  = "FilterData"
  aArgs(2).Value = aFilterData
  xExporter.filter( aArgs() )
End Sub

Sub resizeImageByWidth(uneImage As Object, largeur As Long)
   Dim leBitMap As Object, Proportion As Double
   Dim Taille1 As New com.sun.star.awt.Size
   LeBitmap = uneImage.GraphicObjectFillBitmap
   Taille1 = LeBitMap.Size ' taille in pixels !
   Proportion = Taille1.Height / Taille1.Width
   Taille1.Width = largeur ' largeur en 1/100 de mm
   Taille1.Height = Taille1.Width * Proportion
   uneImage.Size = Taille1
End Sub