Is there a problem with: echo get_stylesheet_directory_uri();? [closed]

Question

I've tried: what could cause get_stylesheet_directory_uri() to fail?
But din't try the function there. Unfortunately, it won't work for me.
Developing a WordPress theme. WordPress version is 3.4.2.

Here is the HTML:

<header>
    <div id="branding">
            <div id="top_ad_left"><a href="#"><img src="<?php echo get_stylesheet_directory_uri() ?>/images/ad-top-left.jpg" alt="top-right-ad" title="top-right-ad" width="260" height="90" /></a></div>
            <a href="<?php echo home_url(); ?>/" title="<?php bloginfo( 'name' ) ?>" rel="home">
                <div id="logo"></div>
            </a>
            <div id="top_ad_right"><a href="#"><img src="<?php echo get_stylesheet_directory_uri() ?>/images/ad-top-right.jpg" alt="top-right-ad" title="top-right-ad" width="260" height="90" /></a></div>

            <div id="blog-title"><span><a href="<?php echo home_url(); ?>/" title="<?php bloginfo( 'name' ) ?>" rel="home"><?php bloginfo( 'name' ) ?></a></span></div>
            <?php if ( is_home() || is_front_page() ) { ?>
                <h1 id="blog-description"><?php bloginfo( 'description' ) ?></h1>
            <?php } else { ?>
                <div id="blog-description"><?php bloginfo( 'description' ) ?></div>
            <?php } ?>
        </div><!-- #branding -->

        <div id="access" align="center">
            <div class="skip-link"><a href="#content" title="<?php _e( 'Skip to content', 'your-theme' ) ?>"><?php _e( 'Skip to content', 'your-theme' ) ?></a></div>
            <?php wp_nav_menu( array( 'theme location' => 'primary', 'fallback_cb' => ''  ) ); ?> <!-- enabling custom menus -->
        </div><!-- #access -->

</header>

And here is the CSS:

#branding {
    //margin: 0 0 1.5em 0;
    height: 140px;
}

#top_ad_left{
    float:left;
    position:relative;
    max-width:300px;
    max-height:100px;
    width: 260px;
    height: 90px;
    z-index:9999;
    }

#logo{
    background-image: url('images/logo.png');
    background-repeat: no-repeat;   
    width: 340px;
    height: 60px;
    float:left;
    position:relative;
    margin:0;
    }

#top_ad_right{
    float:right;
    position:relative;
    max-width:300px;
    max-height:100px;
    width: 260px;
    height: 90px;
    z-index:9999;
    }

#blog-title,
#blog-description{
    display:none; /* as they are not needed for the layout */
    }


/* WP MENU
---------------------------------------------------------------*/

.skip-link {
    display: none;
}

Everything is good and fine. The logo is showing perfectly. But the other two images are not displaying. What's the problem? I want something like this image:

With firebug I saw some discoloration in the desired div's anchor (<a></a>). As we can see in blog-title, because they are display:none;
Is there a problem regarding this? The <?php echo get_stylesheet_directory_uri() ?> code is working fine as they are loading images as you can see in firebug image.

The <img> tag's CSS are:

        margin: 0;
        padding: 0;
        border: 0;
        outline: 0;
        vertical-align: baseline;
        background: transparent;