Provide credentials to access image

Provide credentials to access image

I put my application from public to private, and the service i was using to resize images can no longer access my images.
That is logical, however, i would still like to resize my images.
So in terms of that, is there a way to provide credentials to zoho so that the external service that resizes the images can access them?
If not, is there a way that a certain field can be public, while others are private?