The HTML <img> Element (or HTML Image Element) represents an image of the document.

Usage note:
Browsers do not always display the image referenced by the element. This is the case for non-graphical browsers (including those used by people with vision impairments), or if the user chooses not to display images, or if the browser is unable to display the image because it is invalid or an unsupported type. In these cases, the browser may replace the image with the text defined in this element's alt attribute.

Content categories:
Flow content, phrasing content, embedded content, palpable content. If the element has a usemap attribute, it also is a part of the interactive content category.

Permitted content:
None, it is an empty element.

Tag omission:
Must have a start tag and must not have an end tag.

Permitted parent elements:
Any element that accepts embedded content.

DOM interface:
HTMLImageElement

Interaction with CSS:

Regarding CSS, an <img> is a replaced element. It has no baseline, meaning, when used in an inline formatting context with vertical-align: baseline, the bottom of the image will be posed on the container's baseline.

Depending of its type, an image may have an intrinsic dimension, but this is not a necessary condition: a SVG image has no intrinsic dimension, a raster image has one.
