1. Install the ChatGPT app (Android and iOS, Free with in-app purchases) on your smartphone.. 2. Next, sign in with your OpenAI account and move to the “GPT-4” model. 3. Here, you will find a “+” button at the bottom-left corner. Tap on it. 4. You can then tap on the “camera” icon to take a live photo instantly or tap on the “image” icon to upload a photo from your gallery.