Output image in template
When you are working with an asset field you are actually looking at the object so you need to call {{asset.url}} in order to actually output the path to the image or whatever asset you are working with.

{% for asset in entry.projectBanner %}

    &lt;img src="{{asset.url}}&gt;

{% endfor %}


As some additional information I would checkout eager-loading in craft as it can drastically help performance as your website grows!

https://craftcms.com/docs/templating/eager-loading-elements