For example, when your listing that displays correctly, your template provider creates thumbnails and applies CSS to shrink the thumbnail images (see where it shows the max-width, max-height on the right hand side on the image below):

however on the listings where it looks incorrect, your template provider is not applying that css:

My guess is the template provider is incorrectly the <label> tag for your thumbnail images inside the <li> tag on the bad listings, but you'll need to talk with them as the html they are applying to your listings is not stored in your auctiva account (meaning they are revising your listings after its posted). Hope that helps.