First, you don't say what you want to accomplish, so anything anyone answers is, at best, a guess.

Assuming that you want to get all the text from a postscript file, probably your best bet is something like ps2ascii. It's not perfect, but nothing automated can be.

A postscript "image" is really a program which creates an image when run by something which understands postscript. As a program, there are many different ways of producing the same output. In other words, extracting all the text, in the order it appears in the printed output, is, in the general case, a guess.