Simple question hopefully, but do we simply put in a nice description with keywords etc, or do we need a code format?
Do you mean the Alt tag? If so, my understanding is that it should describe the image for screen readers, so no fancy code required.
I thought it would be simple, but just wanted to check.
If, for whatever reason, the image does not load (show) the Alt text will show instead. Search engines also will use the alt tag. Google the phrase: “Is image alt tag important”