The Journal runs down the rules:
● Avoid using the wire-service description verbatim. Write your own caption.
● Provide only relevant information. Use the nut graf from the story as a guide.
● Describe the action only if it is pertinent to the article.
● Double-check facts against the article, with the reporter or using Google. If the story alleges any misconduct or wrongdoing, please take extra care in confirming the person/people and details. Confirm the identity of alleged wrongdoers in the photo with the reporter, and don’t rely on the caption information from the provider.
● Avoid being overly descriptive with unnecessary details, such as product model numbers and time of day. (Descriptions of military equipment and guns have led to several corrections, so be 100% sure or avoid being specific.)
● If the figures in the photo are obviously shaking hands (or talking, hugging or high-fiving) there is no reason to mention it in the caption.
● Consider a time element, especially if it is an older photo. Readers will assume that a photo was recently taken unless told otherwise. Apple CEO Tim Cook, at the WSJD Live conference in October, discussed the design of the company’s new smartwatch.
● If the time element isn’t relevant to the action, the present tense or present-participle form is used: A boy watches a bulldozer prepare for the construction of housing units in a West Bank settlement. Or: A boy watching a bulldozer prepare for construction of housing units in a West Bank settlement.
● If the time element is essential, use the participle form or the past tense: A boy watching a bulldozer prepare for the construction of housing units in a West Bank settlement on Monday. Or: A boy watched as a bulldozer prepared for the construction of housing units in the West Bank on Monday.
● Use commas, not parentheses, around identifiers such as right, left or wearing hat.
● Add a period to captions that are more than a nameline, even if they are sentence fragments.
● Forgo the constructions above and shown.
● Use single quotes, as in headlines: Amy Adams starred in ‘American Hustle.’
● Add SEO keywords for digital captions.
● Keep it concise in one sentence, if possible.
Slate improves upon some real-world examples:
Bad: Bruce Miller of the San Francisco 49ers was arrested on Thursday for domestic violence.
Good: Bruce Miller of the San Francisco 49ers was arrested on Thursday for domestic violence. Above, Miller during a game on Dec. 15, 2013
Good: Sen. Ron Wyden at a hearing on March 5, 2014, on Capitol Hill in Washington.
Bad: Hannibal Buress, noted Internet spirit animal.
Good: Hannibal Buress, noted Internet spirit animal, performs on May 19, 2013, in Culver City, California.
Bad: Digital spray painting.
Good: Digital spray painting at the new Google store in [location] on [date].