The type of adaptation/interpretation of imagery needed depends on what type of vision impairment we're talking about.

My daughter is a "light perception and form only" blind 2-year-old and I also braille and adapt materials for a "light-perception only" blind 2nd grader full-time. Here are some methods I use:

-- embossing machine which is hooked up to a computer, and/or a braille-writer to create images in Braille dots.
-- quick-draw paper that you use water-based markers on and it instantly swells while the person is drawing
-- puff paint
-- tactile "rubbings" -- for example, you can take a crayon over a screen and feel the image being drawn or use special tools or hard objects to "draw" raised / textured lines.
-- tactile diagrams and books on specific topics
-- and of course, the actual objects themselves are the best way to "see" how things look. For example, my student just learned an introduction to plants. We had on hand this pretty pricey tactile diagram kit which showed the leaves, plants, stem, roots, etc. on raised hard plastic. I also brought in an actual plant that he could feel all the parts. The latter was much more understandable to him. And more fun. :) that sort of experiential knowledge is what some people who are blind lack. Those direct, hands-on experiences are very important.

APH (American Printing House) has a lot of supplies for the things listed above if you want to get an idea of what is used.

Just curious -- why do you ask?