To download all of the photos on your iPhone, you'll need to connect your device to a computer and use the iTunes software. Once your iPhone is connected, open iTunes and click on the device icon in the upper-left corner. Then, click on the "Photos" tab in the middle of the screen. From here, you can select how you want to sync your photos - either by selecting "All Photos" or by choosing a specific album. Finally, click on the "Sync" button in the bottom right corner of the screen.