This image is for Signpost images. Usage is documented at {{Signpost draft helper}}, along with other such templates. Here is the section of that template pertaining to images:

Sidebar images

To put an image in your article, use the following code

[[File:|center|300px|alt=Placeholder alt text]]
CAPTION
{{Wikipedia:Wikipedia Signpost/Templates/Filler image-v2
 |image=
 |size=300px
 |alt=Placeholder alt text
 |caption=CAPTION
 |fullwidth=no
}}

This will create the file on the right. Keep the 300px in most cases. If writing a 'full width' article, change |fullwidth=no to |fullwidth=yes.

Inline images

Placing 

{{Wikipedia:Wikipedia Signpost/Templates/Inline image
 |image=
 |size=300px
 |align=center
 |alt=Placeholder alt text
 |caption=CAPTION
}}

will instead create an inline image like below

[[File:|300px|center|alt=Placeholder alt text]]
CAPTION

You can add the capcenter parameter to make the caption box centered (do this if you want it to be centered on a fullwidth page; it sets the div of the caption to margin: 0 auto.) 

{{Wikipedia:Wikipedia Signpost/Templates/Inline image
 |image=
 |size=300px
 |align=center
 |alt=Placeholder alt text
 |caption=CAPTION
 |capcenter=yes
}}

will instead create an inline image like below

[[File:|300px|center|alt=Placeholder alt text]]
CAPTION

Technical

[edit]

This template uses two CSS classes, which are styled by Wikipedia:Wikipedia_Signpost/Templates/master.css and Wikipedia:Wikipedia_Signpost/Templates/external.css.

Image wrapper, contains the iumage itself.
Caption -- warning! this contains inline styles in the template still! because it parses template params (This can be fixed in theory)

















Wikipedia:Wikipedia Signpost/Templates/Inline_image/doc