Hm, the appendix does give a step-by-step description of the process and example filename... what kind of pics are you asking for? There's no way to do this in the GUI, as this is a command-line only feature and therefore only supports text input, hence the text instructions
Are you familiar with the use of command line instructions? If not then reading up on that would be an important first step (the manual doesn't cover this since it's outside the scope of REXPaint itself--there are several different ways to do it through your OS and it will depend on what you're using and what your own preferences are).
There are a couple different purposes for which you might be doing this (two are described in the manual), so what is it that you're trying to do? For example where's your image?
