There are undocumented features in all the widgets now to allow users to customize things a bit. Adding this before your widget <script> tag will give you access to them:
<script language="javascript">
window.centovacast = {
options: {
recenttracks: {
poll_limit: 60, // number of times to update the tracks list before stopping
poll_frequency: 60000, // how often (in milliseconds) to poll the server
track_limit: 0, // number iof tracks to display (0 to display all on file)
show_covers: 1, // 1 to show covers, 0 to hide
buy_target: '_blank' // '_blank' to open in new window, '' to open in same window
}
}
};
</script>
Tweak as needed (in this case, set show_covers to 0) to achieve whatever effect you're looking for.
As always, the overall appearance is configured using CSS.