Wondering what to put in the description field on an image? A quick guide:
1. Just say what's in the image--you don't need to say it's an image.
2. Describe only what's relevant to the conversation. "Annalee writing in a notebook" or "An example of candid portraiture" or "A person using a fountain pen" are all good captions of the same image, in different contexts.
3. All text that's meant to be read should be transcribed. Screencap? Transcribe. Sign in background of selfie? Don't transcribe.