ImageKit.io provides certain features to secure your images and restrict the transformations that can be performed. Implementing these security features will stop the unauthorized use of your image URLs.
Enable 'Restrict Unnamed Image Transformations' and click on 'Save'.
Restrict unnamed image transformation setting in ImageKit.io dashboard
Enable 'Restrict Unsigned Image URLs' and click on 'Save'.
Restrict unsigned image setting in ImageKit.io dashboard