Gray-level image of JPEG i've added to workspace

I'm having trouble turning the colored image JPEG I've added to my workspace. I have been using the following code: image(tw2); colormap(gray); But this doesn't work and there are no errors. Any ideas?

Answer 1

[Image Analyst]

What does "turning" mean to you? Applying a color map? Rotating? Flipping? Transforming in some other way? Color maps don't apply to color images , only to gray scale or indexed images. Did you know that? A color image is already color so there are no indexes that you can use to replace the color with a color selected from an N by 3 colormap array.