SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<div class="MainImage"><p>111111</p></div>
<div class="MainImage"><p>222222</p></div>
<div class="MainImage"><p>333333</p></div>
<div class="MainImage"><p>444444</p></div>

CSS

.MainImage { display: none; position: absolute; }

JavaScript

var Idx = 0; 
var IntervalKey = setInterval(auto, 5000);

function auto() {
  $(".MainImage").hide().eq(Idx).fadeIn(1000);
  Idx++;
  if(Idx>3) Idx = 0;
};

$(".botao-imagem").click(function(){
  Idx = $(".botao-imagem").index(this);
  auto();
});