Add image caption using app or mobile device?

Is there a way to add image captions to gallery photos using either the app (iPhone) or mobile device? I can add the captions so they are displayed in my gallery from my PC but I can't find a way to add them using the app on my mobile device. I can add/delete images and re-arrange the gallery but there doesn't seem to be a way to add a caption that will be displayed below the image when I upload a new image to the gallery using the app. Thanks in advance.