var namesVec_a = new Array("importacao_bt1.jpg", "importacao_bt1_1.jpg");
var root='images/';

function toggle_a(image,showorhide){
if (showorhide=="show") {image.setAttribute('src',root+namesVec_a[0]);}
if (showorhide=="hide") {image.setAttribute('src',root+namesVec_a[1]);}

nr = image.getAttribute('src').split('/');
nr = nr[nr.length-1]

if(nr==namesVec_a[0]){image.setAttribute('src',root+namesVec_a[1]);}
else{image.setAttribute('src',root+namesVec_a[0]);}

}