Good afternoon!
According to the Guidelines and Standards for Tactile Graphics section 5.2, the preferred order for information related to a graphic would be:
- heading
- caption
- TN
- key
- graphic
- source
If the description of your illustration appears to be a caption that applies only to the graphic and is not part of the regular surrounding text, I would suggest placing it before the graphic even if it appears below or after the illustration in print.
However, section 5.2 also states that for each print graphic, the transcriber must "decide how these elements may be presented to the reader in the most understandable order and format." If for some reason you felt it would be more readable or useful to place the description after the graphic, it would be acceptable to do so.
Sincerely,
Rebecca