Linkchecker surrounds broken link with images.
This looks like this:
<li>
<img src="/libs/cq/linkchecker/resources/linkcheck_o.gif" alt="invalid link: /content/site/home/es.html/cat=cat1" title="invalid link:/content/site/home/es.html/cat=cat1" border="0">
cat1
<img src="/libs/cq/linkchecker/resources/linkcheck_c.gif" border="0">
</li>This can cause huge images if some CSS targets <img> and tells them to be max-width:100%;
The following CSS targets these image
img[src^="/libs/cq/linkchecker/resources/linkcheck_"] {
width: auto;
}