Hello guys. I develop an application and I need to take photos of some documents. Then I send this photos to server. If the upload operation is successful then I display that photo in a collection view. The problem is if the user takes another photo before the previous one's upload process completed then the upload process restart and the previous photo can not be uploaded. How can I upload photos one by one even if it is taken very fast? NSOperationQueue is good to use for that?