Does IOS require consent to Upload photos

I run a photo printing business and have engaged a developer to develop an APP whereby customers select their phone photos, design a photobook and upload for me to print.
My developer informs me that over and above consent to access photos, that my APP requires consent to upload and this must be done via notifications. If not followed, APPLE may reject my APP due to this.

Questions
  1. Must there be a secondary consent to upload photos after my APP being granted access to the photos needed?

  2. Must the consent be sought via a notification?

  3. If it must be sought via notification, what if the customer has switched off notifications?

Does IOS require consent to Upload photos
 
 
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