Replace post/page titles with an image in WordPress

I would actually handle this with CSS. In your style.css file add something like this:

.page-title h1 {
    text-indent: -9999px;
    background: url(images/your_logo.png) 10px 10px no-repeat;
    height: 100%;
}

You’ll then make sure that your logo is added to your theme’s images folder. Also, adjust the size of the image accordingly, or you can also adjust the size of the container.

Notice the two 10px values. That’s your top / left offset (I just picked a couple values to show you those). Adjust those to your liking.

Hope that helps a bit, have fun!