NSPhotoLibraryUsageDescription key must be present in Info.plist to use camera roll

Question

Thanks @rmaddy, I added this just after other key-string pairs in Info.plist and fixed the problem:

<key>NSPhotoLibraryUsageDescription</key>
<string>Photo Library Access Warning</string>

Edit:

I also ended up having similar problems on different components of my app. Ended up adding all these keys so far (after updating to Xcode8/iOS10):

<key>NSPhotoLibraryUsageDescription</key>
<string>This app requires access to the photo library.</string>
<key>NSMicrophoneUsageDescription</key>
<string>This app does not require access to the microphone.</string>
<key>NSCameraUsageDescription</key>
<string>This app requires access to the camera.</string>

Checkout this developer.apple.com link for full list of property list key references.

Full List:

Apple Music:

<key>NSAppleMusicUsageDescription</key>
<string>My description about why I need this capability</string>

Bluetooth:

<key>NSBluetoothPeripheralUsageDescription</key>  
<string>My description about why I need this capability</string>

Calendar:

<key>NSCalendarsUsageDescription</key>
<string>My description about why I need this capability</string>

Camera:

<key>NSCameraUsageDescription</key>
<string>My description about why I need this capability</string>

Contacts:

<key>NSContactsUsageDescription</key>
<string>My description about why I need this capability</string>

FaceID:

<key>NSFaceIDUsageDescription</key>
<string>My description about why I need this capability</string>

Health Share:

<key>NSHealthShareUsageDescription</key>
<string>My description about why I need this capability</string>

Health Update:

<key>NSHealthUpdateUsageDescription</key>
<string>My description about why I need this capability</string>

Home Kit:

<key>NSHomeKitUsageDescription</key>
<string>My description about why I need this capability</string>

Location:

<key>NSLocationUsageDescription</key>
<string>My description about why I need this capability</string>

Location (Always):

<key>NSLocationAlwaysUsageDescription</key>
<string>My description about why I need this capability</string>

Location (When in use):

<key>NSLocationWhenInUseUsageDescription</key>
<string>My description about why I need this capability</string>

Microphone:

<key>NSMicrophoneUsageDescription</key>
<string>My description about why I need this capability</string>

Motion (Accelerometer):

<key>NSMotionUsageDescription</key>
<string>My description about why I need this capability</string>

NFC (Near-field communication):

<key>NFCReaderUsageDescription</key>
<string>My description about why I need this capability</string>

Photo Library:

<key>NSPhotoLibraryUsageDescription</key>
<string>My description about why I need this capability</string>

Photo Library (Write-only access):

<key>NSPhotoLibraryAddUsageDescription</key>
<string>My description about why I need this capability</string>

Reminders:

<key>NSRemindersUsageDescription</key>
<string>My description about why I need this capability</string>

Siri:

<key>NSSiriUsageDescription</key>
<string>My description about why I need this capability</string>

Speech Recognition:

<key>NSSpeechRecognitionUsageDescription</key>
<string>My description about why I need this capability</string>

MY FAVORITE WAY TO DO IT

1. Open info.plist

2. Click this button to add a new key

3. Scroll down to find Privacy - Photo Library Usage Description

4. Select it, then add your description on the right

Add following code in info.plist file

<key>NSPhotoLibraryUsageDescription</key>
<string>My description about why I need this capability</string>

You need to paste these two in your info.plist, The only way that worked in iOS 11 for me.

    <key>NSPhotoLibraryUsageDescription</key>
    <string>This app requires access to the photo library.</string>

    <key>NSPhotoLibraryAddUsageDescription</key>
    <string>This app requires access to the photo library.</string>

For camera access use:

<key>NSCameraUsageDescription</key>
<string>Camera Access Warning</string>

As of now August 2021, not only we have to add this :

<key>NSPhotoLibraryUsageDescription</key> 
<string>We need access to photo library so that photos can be selected</string>

but also need to add this to info.plist file inside iOS folder in order to work properly

<key>NSPhotoLibraryAddUsageDescription</key>    
<string>This app requires access to the photo library.</string>