As example (DEMO):
HTML:
<div class="header">
<img src="img/logo.png" alt="logo" />
<h1>My website name</h1>
</div>
CSS:
.header img {
float: left;
width: 100px;
height: 100px;
background: #555;
}
.header h1 {
position: relative;
top: 18px;
left: 10px;
}
DEMO