Mystique 3.1: Surpress thumbnail if no thumbnail is found

Hi! I’m running Mystique 3.1 with a child theme enabled. I have thumbnails turned on, and they display on post summaries at the default of 90×90, which is dandy. But I hate the fact that an empty gray “image placeholder” appears for posts which don’t have a thumbnail assigned. I suppose I could modify the CSS to display a different “specific” image rather than the gray box, in the event that no thumbnail is found — BUT, I’d rather just suppress the thumbnails entirely.

I did try this trick, which comes close. In my style.css file, within my child theme, I entered the following:

.no-img {
display: none;
}

The only problem with this method is that it leaves a tiny “invisible” element next to the headline of the post that “pushes” the headline over by several pixels, making it look as if the headline is “indented.” Which just looks weird.

I’ve looked all over and can’t find anyone else even asking this question. Is there a way to show thumbnails by default, but hide the thumbnail for a post if no thumbnail is found associated with it?

If you want, you can check my website at dachshundband.com. Run Firebug on it to examine the CSS code for the headlines, and you’ll see what I’m talking about.