If you don't mind implementing a hack you could try the following:
open the file joomlaroot/components/com_gnosis/views/category/tmpl/default.php
Find the following code near line 169:
$definitionstriped = substr(strip_tags($item->definition), 0, $this->params->get('glcwordsdefsize'));
Change it to this:
$definitionstriped = substr($item->definition, 0, $this->params->get('glcwordsdefsize'));
Basically we just removed the "strip_tags()" to prevent the image tags from being deleted. I may add an option in the future to choose to strip the tags from list views or not in the future.
Let me know if it works!