12.2.1 Image Syntax

Here is the basic synopsis of the @image command:

     @image{filename[, width[, height[, alttext[, extension]]]]}

The filename argument is mandatory, and must not have an extension, because the different processors support different formats:

• TeX reads the file filename.eps (Encapsulated PostScript format).
• PDFTeX reads filename.pdf (Adobe's Portable Document Format).
• makeinfo includes filename.txt verbatim for Info output (more or less as if it was an @example).
• makeinfo uses the optional fifth argument extension to @image for the filename extension, if it is specified. For example:

            @image{foo,,,,.xpm}
       

  will cause makeinfo to look for foo.xpm before any others.

The width and height arguments are described in the next section.

For TeX output, if an image is the first thing in a paragraph, for example if you want two images side-by-side, you must precede it with @noindent (see @noindent). Otherwise it will be displayed on a line by itself. If you want it centered, use @center (see @titlefont @center @sp).

When producing html, makeinfo sets the alt attribute for inline images to the optional alttext (fourth) argument to @image, if supplied. If not supplied, makeinfo uses the full file name of the image being displayed. If you want an empty alt string, use @-. The alttext is taken as Texinfo text, so special characters such as `"' and `<' and `&' are escaped in the HTML and XML output.

If you do not supply the optional extension (fifth) argument, makeinfo first tries filename.png; if that does not exist, it tries filename.jpg. If that does not exist either, it complains. (We cannot support GIF format directly due to software patents.)

In Info output, makeinfo writes a reference to the binary image file (trying filename suffixed with extension, .extension, .png, or .jpg, in that order) if one exists. It also literally includes the .txt file if one exists. This way, Info readers which can display images (such as the Emacs Info browser, running under X) can do so, whereas Info readers which can only use text (such as the standalone Info reader) can display the textual version.

The implementation of this is to put the following construct into the Info output:

     ^@^H[image src="binaryfile" text="txtfile"
                alt="alttext ... ^@^H]

where `^@' and `^H' stand for the actual null and backspace control characters. If one of the files is not present, the corresponding argument is omitted.

The reason for mentioning this here is that older Info browsers (this feature was introduced in Texinfo version 4.6) will display the above literally, which, although not pretty, should not be harmful.