Your uploaded image and the generated formats are stored on our server for security reasons, even after a download link has expired. If you use the service without logging in, we store an anonymized identifier of your access (not a readable IP address). This allows us to trace misuse. You can't download your original image again, you only get the finished formats with a watermark. Other users can't see your covers.
If you delete a cover as an artist, it disappears from your list. Internally, it is kept for security reasons.