react-native : How to check if all images are added to array

Question

I am using react-native ImagePicker to select photos and then save it in AWS S3. Every thing works fine but I have one problem.

Problem: I select 3 images using ImagePicker and I am loading an activity indicator when images are uplaoding. I want to turn off the activity indicator when all 3 images are added to my array.

But I don't know how to check if all 3 images are added to the array.

This is my code:

ImagePicker.openPicker({
      multiple: true,
      maxFiles: 3
    }).then(response => {

   ...

    let image = {
            uri: response.uri,
            width: newWidth,
            height: newHeight,
            name: _fileName,
            type: 'image/png'
          }
          const config = {

            bucket: 'bucket',
            region: 'ap-northeast-2',
            accessKey: 'mykey',
            secretKey: 'secretkey',
            successActionStatus: 201
          }

    RNS3.put(image, config)
            .then(responseFromS3 => {

              this.setState({
                imageUrl: [...this.state.imageUrl, responseFromS3.body.postResponse.location]
              }, 
//Every time when image is added the call back below is called. Which is what I don't want.
//I want the call back to be called when all three images are added the the array.   
()=> {this.setState({activityIndicator:false})
//I want to change the status of my activityIndicator to false when all 3 images are added to the array.
//However, this.setState({activityIndicator:false}) is called when one Image is added the to array.
                      })
                    })
                  }).catch((err) => {
                   console.log(err);
                 })
               })
            }).catch(err => {
              this.setState({loadingImageGifVisible:false})
            })
          }