def initialize(anchor, options={})
      @anchor = anchor
      @hyperlink = nil
      @anchor.drawing.worksheet.workbook.images << self
      parse_options options
      start_at(*options[:start_at]) if options[:start_at]
      yield self if block_given?
      @picture_locking = PictureLocking.new(options)
      @opacity = (options[:opacity] * 100000).round if options[:opacity]
    end
Creates a new Pic(ture) object
@param [Anchor] anchor the anchor that holds this image
@option options [String] :name
@option options [String] :descr
@option options [String] :image_src
@option options [Array] :start_at
@option options [Integer] :width
@option options [Integer] :height
@option options [Float] :opacity - set the picture opacity, accepts a value between 0.0 and 1.0