[DotNetDevelopment] [openxml sdk] convert OpenXmlElement into ImagePart

[lszk]

I want to create ImagePart object from OpenXmlElement. I have code:

 public OpenPicture(OpenXmlElement element, ref int elementNumber)
        {
            this.elementNumber = ++elementNumber;
            ImagePart part = null;
            OpenXmlPartWriter writer = new OpenXmlPartWriter(part);
            writer.WriteElement(element);
            Parse(part);

            FillParameters();
        }

This code generate System.ArgumentNullException. How to write it
properly? I can't create instance of ImagePart, because his
constructor is internal.