Yes, you can delete images. It's the record's blockchain timestamp that you can't delete. Not the image. The record is fingerprinted on the blockchain forever but can only be verified with access to the original record's data.
Go to Copyright detail
To delete an image go to the copyright detail page by clicking the image in the Dashboard or Vault.
Click edit and the delete button will appear.
Click the delete button. For precaution we ask you the image's title. Then the image is permanently deleted.