Your memory card photos may not be showing in your phone gallery for several reasons: 1. The memory card is not properly inserted or recognized by your phone. 2. The photos are in an unsupported format for your gallery app. 3. There could be issues with file directory or permissions. 4. Your phone's gallery app might need to be refreshed or updated. 5. Your phone doesn’t recognize the photos properly. To fix the issue where your phone gallery doesn't show pictures on the SD card,  you can reboot the phone, and then your phone will recognize the memory card again.