Should the description of a picture be above it or below?

Text that serves as the description of an image should always go below the image, because it is a description of the image, meaning the image is the source of context. This is the same reason that images are placed below headlines.

1. What makes a good image description?

What makes a good image description?

It should be concise so that it doesn't take too long for people to absorb all the content, especially if there are multiple images. And it should be descriptive enough that it describes all the essential aspects of the image.