I just completed an article on the ServiceNow community regarding how to support copy/paste on the ServiceNow portal.

The article does not require in depth knowledge of SerivceNow. In the guide some of the features of the ServicePortal comes into play to facilitate a relatively simple solution to the challenge of supporting copy / paste of images, most often screenshots, from users.

You can read the full article here: https://community.servicenow.com/docs/DOC-7490