function imageSizeToggle (img) {
	// store an original value for the "thumbnail size"
	if (! img.shrinkWidth)	img.shrinkWidth = img.width + 'px';
	if (! img.shrinkHeight)	img.shrinkHeight = img.height + 'px';
	
	// now set the image's height & width depending on if it is
	// at full height or in thumbnail mode
	img.style.width=(img.style.width != 'auto'? 'auto' : img.shrinkWidth);
	img.style.height=(img.style.height != 'auto'? 'auto' : img.shrinkHeight);
}