@image command results in the following special directive
within the Info file (see Images):
<image> = ^@^H[image src="<image file>" (text="<txt file contents>")? (alt="<alt text>")? ^@^H]
The line breaks and indentation in this description are editorial; the whitespace between the different parts of the directive in Info files is arbitrary.
In the strings <image file>, <txt file contents> and <alt text>, ‘"’ is quoted as ‘\"’ and ‘\’ is quoted as ‘\\’. The txt and alt specifications are optional.
The alt value serves the same purpose as in HTML: A prose description of the image. In text-only displays or speech systems, for example, the alt value may be used instead of displaying the (typically graphical) <image file>.
The <txt file contents>, if present, should be taken as an ASCII representation of the image, for possible use on a text-only display.
The format does not prescribe the choice between displaying the <image file>, the <alt text> or the <txt file contents>.