.fluid_img {
  height: auto;
  width: auto;
  max-width: 100%;
}

<img class="fluid_img" src="..." style="width: 50px; height: 100px;">

$('<img>').src('...').css({width: 50, height: 100});

#myimage {
 background: url(yourimage);
 widthe: 100px;
 height:200px;
 display:inline-block;
}

<div id="myimage"></div>

.myimage {
    display: -moz-inline-stack;
    display: inline-block;
    zoom: 1;
    *display: inline;
}

<img class="myimage" style="width:100px;height:200px">