var x = 0
	var mainpic = new Array();

mainpic[0] = new Image();
mainpic[0].src = 'gfxabout/main1.jpg';

mainpic[1] = new Image();
mainpic[1].src = 'gfxabout/main2.jpg';

mainpic[2] = new Image();
mainpic[2].src = 'gfxabout/main3.jpg';

mainpic[3] = new Image();
mainpic[3].src = 'gfxabout/main4.jpg';

mainpic[4] = new Image();
mainpic[4].src = 'gfxabout/main5.jpg';

mainpic[5] = new Image();
mainpic[5].src = 'gfxabout/main6.jpg';

mainpic[6] = new Image();
mainpic[6].src = 'gfxabout/main7.jpg';

	function setImageDisplay()
	{
		var picBeingShown = document.getElementById("mainDisplay");
		picBeingShown.src = mainpic[x].src;
	}

	function setFirstGrey()
	{
		var firstButtonGreyed = document.getElementById("firstButton");
		firstButtonGreyed.style.color="#999999";
		firstButtonGreyed.style.cursor="default";
	}

	function setFirstUngrey()
	{
		var firstButtonUngreyed = document.getElementById("firstButton");
		firstButtonUngreyed.style.color="#669999";
		firstButtonUngreyed.style.cursor="pointer";
	}

	function setPreviousGrey()
	{
		var previousButtonGreyed = document.getElementById("previousButton");
		previousButtonGreyed.style.color="#999999";
		previousButtonGreyed.style.cursor="default";
	}

	function setPreviousUngrey()
	{
		var previousButtonUngreyed = document.getElementById("previousButton");
		previousButtonUngreyed.style.color="#669999";
		previousButtonUngreyed.style.cursor="pointer";
	}

	function setNextGrey()
	{
		var nextButtonGreyed = document.getElementById("nextButton");
		nextButtonGreyed.style.color="#999999";
		nextButtonGreyed.style.cursor="default";
	}

	function setNextUngrey()
	{
		var nextButtonUngreyed = document.getElementById("nextButton");
		nextButtonUngreyed.style.color="#669999";
		nextButtonUngreyed.style.cursor="pointer";
	}

	function setLastGrey()
	{
		var lastButtonGreyed = document.getElementById("lastButton");
		lastButtonGreyed.style.color="#999999";
		lastButtonGreyed.style.cursor="default";
	}

	function setLastUngrey()
	{
		var lastButtonUngreyed = document.getElementById("lastButton");
		lastButtonUngreyed.style.color="#669999";
		lastButtonUngreyed.style.cursor="pointer";
	}

	function setPicNumber()
	{
		var picNumber = x+1;
		document.getElementById("picNo").innerHTML=" "+picNumber+" of 7";
	}

	function setCaption()
	{
		if (x==0)
			{
			document.getElementById("picturecaption").innerHTML="The Thames sailing barge was the workhorse of coastal transport until well into the 20th Century. The design and rig evolved in a very specific way to suit the locations, conditions and requirements of her trade";
			document.getElementById("pictureCredit").innerHTML="Photograph: Lynne Tait";
			}
		else if (x==1)
			{
			document.getElementById("picturecaption").innerHTML="The barge’s box-like hull maximised her load-carrying capacity, while the flat bottom not only gave her a shallow draught, but also meant she could take the ground at low water";
			document.getElementById("pictureCredit").innerHTML=" ";
			}
		else if (x==2)
			{
			document.getElementById("picturecaption").innerHTML="The lifting leeboards on either side, instead of a fixed keel, gave windward sailing performance while maintaining the barge’s shallow draught, which enabled her to trade in the shallowest of waters";
			document.getElementById("pictureCredit").innerHTML="Photograph: Bob Ratcliffe";
			}
		else if (x==3)
			{
			document.getElementById("picturecaption").innerHTML="The mizzen sail is sheeted onto the outer end of the rudder, so that when the wheel is turned to tack the barge, the mizzen is forced up into the wind, helping to turn the stern";
			document.getElementById("pictureCredit").innerHTML=" ";
			}
		else if (x==4)
			{
			document.getElementById("picturecaption").innerHTML="The high mainmast and tall topsail — its peak is about 100 feet above the waterline — can catch the wind above the trees in a land-locked creek, or above warehouses around a sheltered harbour";
			document.getElementById("pictureCredit").innerHTML=" ";
			}
		else if (x==5)
			{
			document.getElementById("picturecaption").innerHTML="Repertor’s bow plating was extensively rebuilt in late 2008, giving the opportunity to repaint the hull according to the original Horlocks livery (see photo 6 in the History gallery)";
			document.getElementById("pictureCredit").innerHTML="Photograph: Neil Hammersley";
			} 
		else if (x==6)
			{
			document.getElementById("picturecaption").innerHTML="Repertor’s topmast broke too late in 2009 to be replaced, so we re-rigged our bowsprit and sailed as a ‘stumpy’ for the rest of the season: this rig is typical of barges before topmasts became widely used in the 19th Century";
			document.getElementById("pictureCredit").innerHTML="Photograph: Neil Hammersley";
			}
	}

	function firstImage()
	{
		x = 0
		setImageDisplay();
		setFirstGrey();
		setPreviousGrey();
		setNextUngrey();
		setLastUngrey();
		setPicNumber();
		setCaption()
	}
	
	
	function previousImage()
	{
		x--
		if (x<0)
			{
			x = 0
			}
		else if (x==0)
			{
			setFirstGrey();
			setPreviousGrey();
			}
		else if (x==5)
			{
			setNextUngrey();
			setLastUngrey();
			}
		setImageDisplay();
		setPicNumber();
		setCaption()
	}
	
	
	function nextImage()
	{
		x++
		if (x>6)
			{
			x = 6
			}
		else if (x==6)
			{
			setNextGrey();
			setLastGrey();
			}
		else if (x==1)
			{
			setFirstUngrey();
			setPreviousUngrey();
			}
		setImageDisplay();
		setPicNumber();
		setCaption()
	}
	
	
	function lastImage()
	{
		x = 6
		setImageDisplay();
		setFirstUngrey();
		setPreviousUngrey();
		setNextGrey();
		setLastGrey();
		setPicNumber();
		setCaption()
	}