var imgNext = new Image();

var imgArray = new Array(
	'assets/random_001.gif',
	'assets/random_002.gif',
	'assets/random_003.gif',
	'assets/random_004.gif',
	'assets/random_005.gif',
	'assets/random_006.gif',
	'assets/random_007.gif',
	'assets/random_008.gif',
	'assets/random_009.gif',
	'assets/random_010.gif'
);

function getRndImg(imgObj,imgArr) {
	
	var srcOld = imgObj.src;

	if ((imgNext.src != '') && (imgNext.src != imgObj.src)) {
		imgObj.src = imgNext.src;
	}
	
	var srcNew = imgArr[Math.floor(imgArr.length * Math.random())];
	if (imgObj.src == srcNew) {
		getRndImg(imgObj,imgArr);
	} else {
		imgNext.src = srcNew;
	}

	if (imgObj.src == srcOld) { // catches only the first case
		getRndImg(imgObj,imgArr);
	}

}