Re: XPM images

[Richard Stallman]

    My apologies. Only two functions are supposed to be used from the
    "outside": `xpm-image-from-file' and `xpm-image-from-string'.

Those names suggest functions that return an xpm image.  However, this
file is supposed to convert xpm to ppm.  So those names are confusing.
The function names for functions that return ppm images should
probably say they return ppm images.  At the very least the doc strings
should say so.

    Besides that, the whole
    process of converting to and applying PPM was meant to be
    transparent. What the two main functions `xpm-image-from-string' and
    `xpm-image-from-file' actually return is an image descriptor, as a
    function like `insert-image' takes it as an argument. But I refer to
    the image descriptors in the doc-strings only as "images"; thus
    mimicking the documentation strings of `insert-image', `create-image'
    or `find-image'.

That convention is very hard to understand; I recommend you find
a clearer way to describe this.