The reason this is necessary is that if you hotlink an image from Graphic Audio --
like e.g from this page:
http://www.graphicaudiointernational.net/widdershins-adventures-1-thief-s-covenant.htmlThe image you want is this:

What we see if you hot link the image (copying the GraphicAudio URL) is:

Graphic Audio's webserver will serve the "Please visit Graphic Audio" image instead of the cover if it's called by another site.
One problem is that initially the uploader sees the original image, because your browser has it in its cache from when you visited the site. But everyone else will see the text. If you refresh the page (F5) that will re-fetch the image; you will now see the text instead of the cover.
Alternative image hostshttp://imgur.comhttps://imgbb.com-- and many others. Generally if you create an account rather then using an anonymous upload, the image will have more permanency, though nothing is forever, the sites can shut down, and you can delete images if you need to.
Some will allow you to just paste in the URL of a Graphic Audio image and it will get it and give you a new image link that will work on any site. Saves downloading and uploading the image. Just check you aren't getting the notice instead of the cover.