To use with Stylish on your Jenkins build page

gistfile1.txt

#spinner {
  position: relative;
  top: 0;
  left: 0;
  width: 40px;
  height: 40px;
  background-image:url(http://files.gamebanana.com/img/ico/sprays/_1317-.gif);
  background-position: -1% 90%;
  background-repeat: no-repeat;
  background-size: 40px 40px;
  
  -webkit-transform: scaleX(-1);
  -moz-transform: scaleX(-1);
  -o-transform: scaleX(-1);
  transform: scaleX(-1);
  filter: FlipH;
  -ms-filter: "FlipH";
}

#spinner img {
  display:none;
}

#main-table {
  background: none !important;
}

#main-table:after {
  content: '';
  display: block;
  z-index: -1;
  position: fixed;
  top:0 ;
  left: 0;
  width: 100%;
  height: 100%;
  background-image:url(http://files.gamebanana.com/img/ico/sprays/_1317-.gif);
  background-position: -1% 90%;
  background-repeat: no-repeat;
  opacity: .3;
  
  -webkit-transform: scaleX(-1);
  -moz-transform: scaleX(-1);
  -o-transform: scaleX(-1);
  transform: scaleX(-1);
  filter: FlipH;
  -ms-filter: "FlipH";
  
  -webkit-animation: blink linear 2s infinite alternate;
  -moz-animation: blink linear 2s infinite alternate;
  -o-animation: blink linear 2s infinite alternate;
  animation: blink linear 2s infinite alternate;
}

@-webkit-keyframes blink {
  from { opacity: .3; } to { opacity: .5; }
}

@-moz-keyframes blink {
  from { opacity: .3; } to { opacity: .5; }
}

@-o-keyframes blink {
  from { opacity: .3; } to { opacity: .5; }
}

@keyframes blink {
  from { opacity: .3; } to { opacity: .5; }
}