MOS:CREDITS
A caption is text that appears below an image. Most captions draw attention to something in the image that is not obvious, such as its relevance to the text. A caption may be a few words or several sentences. Writing good captions takes effort; along with the lead and section headings, captions are the most commonly read words in an article, so they should be succinct and informative.

Not every image needs a caption; some are simply decorative. Relatively few may be genuinely self-explanatory. In addition to a caption, alt textfor visually impaired readersshould be added to informative (but not purely decorative) images; see Wikipedia:Alternative text for images.

Some criteria for a good caption 
There are several criteria for a good caption. A good caption

 clearly identifies the subject of the picture, without detailing the obvious;
 is succinct;
 establishes the picture's relevance to the article;
 provides context for the picture;
 draws the reader into the article.

Different people read articles in different ways. Some people start at the top and read each word until the end. Others read the first paragraph and scan through the article's body for other interesting information, looking especially at pictures and captions. Those readers, even if the information is adjacent in the text, will not find it unless it is in the caption. However, it is best not to tell the whole story in the caption, but use the caption to make the reader curious about the subject.

Another way of approaching the job: imagine you're giving a lecture based on the encyclopedia article, and you are using the image to illustrate the lecture. What would you say while attention is on the image? What do you want your audience to notice in the image, and why? Corollary: if you have nothing to say about it, then the image probably does not belong in the article.

Clear identification of the subject 
One of a caption's primary purposes is to identify the subject of the picture. Make sure your caption does that, without leaving readers to wonder what the subject of the picture might be. Be as unambiguous as practical in identifying the subject. What the picture is is important, too. If the image to be captioned is a painting, an editor can give context with the painter's Wikilinked name, the title, and a date. The present location may be added in parentheses: (Louvre). Sometimes the date of the image is important: there is a difference between "King Arthur" and "King Arthur in a 19th-century watercolor".

Photographs and other graphics need not have captions if they are "self-captioning" images (such as reproductions of album or book covers) or when they are unambiguous depictions of the subject of the article. In a biography article no caption is necessary for a portrait of the subject pictured alone; but one might be used to give the year, the subject's age, or other circumstances of the portrait along with the name of the subject.

Succinctness 

Succinctness is using no superfluous or needless words. It is not the same as brevity, which is using a relatively small number of words. Succinct captions have more power than verbose ones. More than three lines of text in a caption may be distracting; instead, further information can be provided in the article body. And remember that readers wanting full detail can click through to the image description page.

Non-visual media 
Because non-visual media imparts no visual information regarding the content of its file, it is often desirable to include a longer description than is typically acceptable with image captions. As with image captions, care should be taken to include enough relevant information in-line so the media file's relevance to the article is made explicit irrespective of the caption. As a general rule, retain broader points in the article body, including specific points in the media file's description field. For example, the statement: "'Yesterday' is one of the Beatles' best-known songs" might be more appropriate for the article body than the statement: "The string arrangement on 'Yesterday' utilises counterpoint, which complements McCartney's vocals by reinforcing the tonic", which might be more appropriate as an Ogg file description, especially if the text pertains to the contents of the media file or supports its fair-use rationale.

Technical images 
Technical images like charts and diagrams may have captions that are much longer than other images. Prose should still be succinct, but the significance of the image should be fully explained. Any elements not included in a legend or clearly labelled should be defined in the caption. A substantial, full discussion of a technical image may be confined to the caption if it improves the structure of the prose in the main article.

For maps and other images with a legend, the  template can be used in the caption instead of (or in addition to) including the legend explaining the color used in the image. This makes the legend more readable, and allows for easy translation into other languages.

Establishing relevance to the article 
A good caption explains why a picture belongs in an article. "The 1965 Ford Mustang introduced the whiz-bang super-speeder" tells the reader why it is worth the trouble to show a photo of a 1965 Ford Mustang rather than just any year of that model car. Links to relevant sections within the article may help draw the reader in (see here for how to do this).

Providing context for the picture 

A picture captures only one moment in time. What happened before and after? What happened outside the frame?

For The Last Supper, "Jesus dines with his disciples" tells something, but add "on the eve of his crucifixion" and it tells much more about the significance. Add "With this meal, Jesus established the tradition of Holy Communion" to get more context if you do not cover that in the article. In such a caption the name of the painter and date provide information on the cultural point of view of the particular representation.

Drawing the reader into the article 
The caption should lead the reader into the article. For example, in History of the Peerage, a caption for :Image:William I of England.jpg might say "William of Normandy overthrew the Anglo-Saxon monarchs, bringing a new style of government." Then the reader gets curious about that new form of government and reads text to learn what it is.

Wording 

 While a short caption is often appropriate, if it might be seen as trivial (), consider extending it so that it adds value to the image and is related more logically to the surrounding text ().
 Sometimes the title-and-subtitle style with a colon works: .
 It is usually unnecessary to state what kind of image is being shown. A map of the world showing NATO member countries can be captioned simply  rather than .
 An artist's rendition of a subject of history should be identified as such to avoid confusing details of actual events or portrait likenesses with artistic renditions of them, which are not always accurate.
 Wikipedia has its technical means of getting readers to the full-size version of the image; therefore amending the caption with a direct link to the image (for example, ) is not appropriate.

Formatting and punctuation 

 Captions normally start with a capital letter.
 The text of captions should not be specially formatted (with italics, for example), except in ways that would apply if it occurred in the main text. Several discussions (e.g. this one) have failed to reach a consensus on whether "stage directions" such as  or  should be in italics, set off with commas, etc. Any one article should use a consistent approach throughout.
 Most captions are not complete sentences, but merely sentence fragments, which should not end with a period or full stop. If any complete sentence occurs in a caption, then all sentences, and any sentence fragments, in that caption should end with a period or full stop.
  (No final period or full stop for lone sentence fragment), not 
  (Period or full stop ends complete sentence)
  (Period or full stop on each when they appear together)

Special situations 
Captions of images in infoboxes and other special situations call for special consideration.

Infoboxes and leading images 
An infobox image and, in the absence of an infobox, a photograph or other image in the article's lead section, serves to illustrate the topic of the article, as such, the caption should work singularly towards that purpose. Depending on the nature of the subject and the image used, the ideal caption can range from none at all to a regular full-sentence caption. The following examples serve to describe the range of situations for particular infobox images:

 No caption – Infoboxes normally display the page name as the title of the infobox. If nothing more than the page name needs to be said about the image, then the caption should be omitted as being redundant with the title of the infobox.
 Short caption – Infoboxes for things that change over time can mention the year of the image briefly, e.g. "Cosby in 2010" for . If the image is of a person doing that for which they are known at an otherwise common event, the correct verb delivers the message, e.g. "Jackson performing in 1988" for . As an additional example, animals may differ from the one pictured, e.g. Noisy miner "Subspecies leachi" in , photographs captioned simply "Male" and "Female" for , and "Publicity photo for Jailhouse Rock (1957)" for . While more detail could be added, consider carefully whether it might distract the reader from the subject of the article or inform the reader about the importance of the subject.
 Full-sentence caption – When the caption can convey the significance of the article by explaining the significance or context of the image, it should. For example, "Angelou recites her poem, 'On the Pulse of Morning', at President Bill Clinton's inauguration, January 1993", . In this situation, take extra care that both the image and the caption stay sharply focused on the whole of the article's subject per MOS:INFOBOX.  gives an example of an informative yet brief full-sentence caption describing the key element (the singular protagonist) depicted and its relationship to the article's subject. The need for a full-length caption in an infobox can generally indicate one of two things: 1) an exceptionally inappropriate image or 2) an image that doesn't really belong in the infobox. Consider this distinction carefully as it depends on how precisely the image applies to the subject as a whole.

Additional descriptive information about the image should be contained in the image description on the image's page.

Other special situations 
Several types of images warrant special treatment:

 Periodic table snippets for each elementno caption needed.
 Infobox images with mission insigniano caption needed, but if there is a description of the symbolism, it should be included on the image description page.
 Other images (especially within infoboxes) where the purpose of the image is clearly nominative, that is, that the picture serves as the typical example of the subject of the article and offers no further informationno caption needed.
 Chemical compound diagrams (as in TNT) could benefit from a mention of the role of the structure in the properties of the compound.
 Group portraits of a few people (presumably related to the article) should list the names of the individuals so that readers can identify individuals. Larger groups should have an index photo with numbered silhouettes and a key listing each person's name.
 When portraits of a person in an article about that person are captioned, they should be captioned with the year. For example, if the photo is of a special occasion, or of historical significance such as Wernher von Braun surrendering to the Americans, the caption should follow the usual style.

Tips for describing pictures 
Here are some details people might want to know about the picture (all are linkable):

 What is noteworthy about the subject of the picture? If there is an article on the subject of the picture, link to it.
 For photographs:
 Where was it taken?
 When was it taken?
 Who took it? (Generally, this is included in the caption only if the photographer is notable.)
 Why was it taken?
 For works of art (see WikiProject Visual arts Art Manual of Style for fuller details):
 Who is the artist?
 What is the title or subject?
 When was the piece completed?
 See proper right for ways of unambiguously describing right and left in images.
 Usually less significant are:
 What is the medium (oil-on-canvas/marble/mixed media...)?
 Where is it located?
 What are its dimensions?

Keep in mind that not all this information needs to be included in the caption, since the image description page should offer more complete information about the picture. If it does not, it may be possible to add it there from reliable sources such as the website of the museum that owns the image.

A caption should never simply link to the article in which it appears, though it may link to a specific section of the article.

Credits 

thumb|The midnight visit of "The Raven" as illustrated by Édouard Manet (1875)
Unless relevant to the subject, do not credit the image author or copyright holder in the article. It is assumed that this is not necessary to fulfill attribution requirements of the GFDL or Creative Commons licenses as long as the appropriate credit is on the image description page. If the artist or photographer is independently notable, though, then a wikilink to the artist's biography may be appropriate, but image credits in the infobox image are discouraged, even if the artist is notable, since the infobox should contain only key facts of the article's subject, per MOS:INFOBOX.

See also 

 MOS:CAPTION (main MoS entry for captions with formatting recommendations)
 
 Wikipedia:Manual of Style/Accessibility/Alternative text for images
 Wikipedia:Images
 Wikipedia:Picture tutorial
 Wikipedia:Uploading images
 Wikipedia:WikiProject Writing Captions

Notes and references

External links 

 Sharp Points: 9 Commandments of Caption Writing