function viewPicture(imageName,imageWidth,imageHeight,alt) {
var top = screen.height/2 - imageHeight/2;
var left = screen.width/2 - imageWidth/2;
newWindow = window.open("","newWindow","width="+imageWidth+",height="+imageHeight+",scrollbars=no,left="+left+",top="+top);
newWindow.document.open();
newWindow.document.write(''+alt+'');
newWindow.document.write('![\"'+alt+'\"](\"'+imageName+'\")
');
newWindow.document.write('');
newWindow.document.close();
newWindow.focus();
}