Displaying image from related CraftCommerce entry
Ok first thing take the s off relatedProduct because each loop is over one relatedProduct ;) - then you can do something like this:

{% for relatedProduct in product.relatedAccessories %}
   {{ relatedProduct.title }} - {{ relatedProduct.accessoryDescription }}
   Url: {{ relatedProduct.yourAssetHandle.first().url }}
{% endfor %}


You should probably protect that by first checking {% if relatedProduct.yourAssetHandle.first()|length %} unless you can be completely certain you will have an asset (required field for example).