var currentImage = 0;

function moveLeft() {
	changeImageTo(currentImage - 1);
	if (currentImage == 0) { document.getElementById('arrow-left').style.visibility = 'hidden'; }
}

function moveRight() {
	changeImageTo(currentImage + 1);
	if (currentImage == totalImages - 1) { document.getElementById('arrow-right').style.visibility = 'hidden'; }
}

function mouseOverLeft() {
	if (currentImage > 0){ document.getElementById('arrow-left').style.visibility = 'visible'; }
}

function mouseOutLeft() {
	document.getElementById('arrow-left').style.visibility = 'hidden';
}
function mouseOverRight() {
	if (currentImage < totalImages - 1){ document.getElementById('arrow-right').style.visibility = 'visible'; }
}

function mouseOutRight() {
	document.getElementById('arrow-right').style.visibility = 'hidden';
}


function changeImageTo(newImage) {
	if (newImage >= 0 && newImage < totalImages) {
		document.mainimage.onload = function () {
			var mainImage = document.mainimage;		
			document.getElementById('imagebox').style.width = mainImage.width + 'px';
			document.getElementById('imagebox').style.height = (mainImage.height+14) + 'px';
    	};
		document.mainimage.src = projectImages[newImage][0];
		document.getElementById('imagetitle').innerHTML = projectImages[newImage][1];	
		currentImage = newImage;
	}
}