function focusImage(img) {
	var strSelectedImageFilter = "?Width=234&Height=325&Pad=1&PadTo=TopLeft";
	var strImageFilter = "?Width=85&Height=118&Pad=1&PadTo=TopLeft";
	
	// main image and text
	var oSelectedImage = document.getElementById("SelectedFeatureImage").getElementsByTagName("IMG")[0];
	var oSelectedImageText = document.getElementById("SelectedFeatureImage").getElementsByTagName("DIV")[0];
	
	// gallery text element
	var oGalleryText = document.getElementById(String(img.id).replace("img_", "div_"));
	
	// temp holding variables
	var strOldSrc = String(oSelectedImage.src).replace(/(\.\S{3})(\?\S*?)$/i, function($0,$1,$2) { return String($1); }) + strImageFilter;
	var strOldAlt = oSelectedImage.alt;
	var strOldText = oSelectedImageText.innerHTML;
	var strOldImgID = oSelectedImage.id;
	var strOldDivID = oSelectedImageText.id;
	var strImgIDBuffer = img.id;
	var strDivIDBuffer = oGalleryText.id;
	
	// wipe the gallery element's id's to stop duplicate id's entering the DOM
	img.id = "ZZZZzzzzZZ";
	oGalleryText.id = "XXxxXXXXxxX";
	
	// set up the main image and text
	oSelectedImage.src = img.src.replace(/(\.\S{3})(\?\S*?)$/i, function($0,$1,$2) { return String($1); }) + strSelectedImageFilter;
	oSelectedImage.alt = img.alt;
	oSelectedImage.id = strImgIDBuffer;
	oSelectedImageText.innerHTML = oGalleryText.innerHTML;
	oSelectedImageText.id = strDivIDBuffer;
	
	// shift the old main image into the gallery
	img.src = strOldSrc;
	img.alt = strOldAlt;
	img.id = strOldImgID;
	oGalleryText.id = strOldDivID;
	oGalleryText.innerHTML = strOldText;
}