I’m a long time user of the Contextual Related Posts plugin for WordPress.

The thing is that if you activate thumbnails, you’ll end up with this kind of ugly list:

Related content block in its default style, a plain vertical bulleted list with each thumbnail stacked above its link

So I’ve written some CSS to beautify this, and make the final result aligns with TwentyEleven (WordPress default theme):

The same block restyled into three equal cards side by side, each thumbnail cropped to fill its tile with the title overlaid at the bottom

And here is the CSS producing the result above: 

#crp_related ul {
    list-style: none;
    float: left;
    margin: 0;
}

#crp_related li,
#crp_related a {
    float: left;
    overflow: hidden;
    position: relative;
    text-align: center;
}

#crp_related li {
    margin: .9em;
    border: 1px solid #ddd;
    padding: 6px;
}

#crp_related li:hover {
    background: #eee;
    border-color: #bbb;
}

#crp_related a {
    width: 150px;
    height: 150px;
}

#crp_related a:hover {
    text-decoration: none;
}

#crp_related img {
    max-width: 150px;
    margin: auto;
}

#crp_related .crp_title {
    position: absolute;
    height: inherit;
    bottom: 6px;
    left: 6px;
    padding: 3px;
    width: 144px;
    /* = 150px - (3px * 2) */
    color: #fff;
    font-size: .9em;
    text-shadow: #000 .1em .1em .2em;
    background: rgb(0.5, 0.5, 0.5);
    background: rgba(0, 0, 0, 0.5);
}

#crp_related li:hover .crp_title {
    background: rgb(0.2, 0.2, 0.2);
    background: rgba(0, 0, 0, 0.8);
}

I’ve integrated this CSS code via a widget, using the same technique I’ve detailed here  .

This CSS was tested against the version 1.7.2 of Contextual Related Posts , and for reference, here is my plugin configuration:

Output options tab of the plugin, setting the heading markup, the list and item tags, and the thumbnail placement and 150 pixel size limits

And FYI, my post default thumbnail is from KDE’s Oxygen icon set , which I found on my system in /usr/share/icons/oxygen/128x128/apps/knotes.png .