function verifyUploadFile(upload) 
{
   var TamanhoString = upload.ctl00$cphMain$updImagePreview.value.length;
   var extensao      = upload.ctl00$cphMain$updImagePreview.value.substr(TamanhoString - 4,TamanhoString);
   var isValid       = false;
   if (TamanhoString != 0 )
   {
		var ext = new Array('.jpg','.jpeg','.gif','.bmp','.png','.tga','.tiff','.psd');
		for(var i = 0; i < ext.length; i++) 
		{ 
			if (extensao.toLowerCase() == ext[i].toString().toLowerCase())
			{
				isValid = true;
				break;
			}
		}
		
		if(!isValid){
		    alert(upload.ctl00$cphMain$hdMessageFileTypeError.value);
		    return isValid;
		}
	}
	else
	{
	    return !isValid;
	}
}