graphicsize.extension boolean
graphicsize.extension Enable the getWidth()/getDepth() extension functions

## Description

If non-zero (and if use.extensions is non-zero and if you're using a processor that supports extension functions), the `getWidth` and `getDepth` functions will be used to extract image sizes from graphics.

The main supported image formats are GIF, JPEG, and PNG. Somewhat cruder support for EPS and PDF images is also available.