private static IntPtr CairoCreateImageFromFile(string imageFilePath, out int imageWidth, out int imageHeight)
      {
         IntPtr cairo_image = IntPtr.Zero;

         imageWidth = 0;
         imageHeight = 0;

         if (imageFilePath.Length != 0)
         {
            var tmpImgFile = System.IO.Path.GetTempPath() + TMP_IMG_NAME;
            using (System.Drawing.Image image = System.Drawing.Image.FromFile(imageFilePath))
            {
               image.Save(tmpImgFile, System.Drawing.Imaging.ImageFormat.Png);

               cairo_image = cairo.cairo_image_surface_create_from_png(tmpImgFile);

               imageWidth = cairo.cairo_image_surface_get_width(cairo_image);
               imageHeight = cairo.cairo_image_surface_get_height(cairo_image);
            }
         }

         return cairo_image;
      }


partial code this is in a loop that processes each image file I want in the PDF


         int imageWidth;
         int imageHeight;
         IntPtr cairo_image = CairoCreateImageFromFile(mImageFile, out imageWidth, out imageHeight);

         cairo_status_t status = cairo.cairo_surface_status(cairo_image);
         if (status != cairo_status_t.CAIRO_STATUS_SUCCESS)
         {
            cairo.cairo_surface_destroy(cairo_image);
            cairo_image = IntPtr.Zero;
         }

         if (cairo_image != IntPtr.Zero)
         {
            NeedCrop(ref imageWidth, ref imageHeight, (int)info.ClipRectWidthInPixels, (int)info.ClipRectHeightInPixels);

            // trim labels are NOT clipped to the piece. Because the clipping region has been established prior
            // to this function we need to save the current state, reset the clipping region and when finished
            // drawing the trim label restore the state
            if ((info.flags & Constants.TrimLabelImage) != 0)
            {
               cairo.cairo_save(cr);
               cairo.cairo_reset_clip(cr);
            }

            // save the current state of cr
            cairo.cairo_save(cr);

            cairo.cairo_translate(cr, locX * scale_coef, locY * scale_coef);

            TransformGroup tg = new TransformGroup();
            tg.Children.Add(new ScaleTransform(imageSize.Width * scale_coef / imageWidth, imageSize.Height * scale_coef / imageHeight));
            tg.Children.Add(imageToPieceTransform);

            cairo_matrix_t crTransform = new cairo_matrix_t(tg.Value.M11, tg.Value.M12, tg.Value.M21, tg.Value.M22, tg.Value.OffsetX, tg.Value.OffsetY);

            cairo.cairo_transform(cr, ref crTransform);

            if (fillPiece && tg.Inverse != null)
            {
               var pattern = cairo.cairo_pattern_create_for_surface(cairo_image);
               cairo.cairo_pattern_set_extend(pattern, cairo_extend_t.CAIRO_EXTEND_REPEAT);

               cairo.cairo_set_source(cr, pattern);

               // invert piece bounds
               var p1 = tg.Inverse.Transform(rTransfBackground.BottomLeft);
               var p2 = tg.Inverse.Transform(rTransfBackground.TopLeft);
               var p3 = tg.Inverse.Transform(rTransfBackground.TopRight);
               var p4 = tg.Inverse.Transform(rTransfBackground.BottomRight);

               cairo.cairo_move_to(cr, p1.X, p1.Y);
               cairo.cairo_line_to(cr, p2.X, p2.Y);
               cairo.cairo_line_to(cr, p3.X, p3.Y);
               cairo.cairo_line_to(cr, p4.X, p4.Y);
               cairo.cairo_close_path(cr);

               cairo.cairo_fill(cr);

               cairo.cairo_pattern_destroy(pattern);
               pattern = IntPtr.Zero;

               // DEBUG: set line color
               //cairo.cairo_set_source_rgb(cr, 1.0, 0.0, 0.0);
            }
            else
            {
               // crop image - move out mask
               cairo.cairo_set_source_surface(cr, cairo_image, -info.clipRectLeft, -info.clipRectTop);

               // mask
               cairo.cairo_rectangle(cr, 0, 0, imageWidth, imageHeight);

               // fill
               cairo.cairo_fill(cr);

               // DEBUG: set line color
               cairo.cairo_set_source_rgb(cr, 0.0, 0.0, 1.0);
            }

            cairo.cairo_surface_destroy(cairo_image);
            cairo_image = IntPtr.Zero;

            // DEBUG: draw image position
            //cairo.cairo_set_line_width(cr, 0.4);
            //cairo.cairo_rectangle(cr, 0, 0, imageWidth, imageHeight);
            //cairo.cairo_stroke(cr);

            // if trim label restore the state (clipping region)
            if ((info.flags & Constants.TrimLabelImage) != 0)
            {
               cairo.cairo_restore(cr);
               // delete the "temp" label file
               File.Delete(mImageFile);
            }

            // restore the saved state of cr
            cairo.cairo_restore(cr);
         }