insertNewImage = (imageWidth, imageHeight) => {
            const newImage = this.svgCanvas.addSVGElementsFromJson({
              element: 'image',
              attr: {
                x: 0,
                y: 0,
                width: imageWidth,
                height: imageHeight,
                id: this.svgCanvas.getNextId(),
                style: 'pointer-events:inherit'
              }
            })
            this.svgCanvas.setHref(newImage, result)
            this.svgCanvas.selectOnly([newImage])
            this.svgCanvas.alignSelectedElements('m', 'page')
            this.svgCanvas.alignSelectedElements('c', 'page')
            this.topPanel.updateContextPanel()
            $id('se-prompt-dialog').setAttribute('close', true)
          }
Insert the new image until we know its dimensions.
@param {Float} imageWidth
@param {Float} imageHeight
@returns {void}