You don’t need to save an image to your startup file like that. Guys is there something wrong with how blender’s palette system works? Look at this file:swatches.blend (381.9 KB)
I was able to add every color from that chart to that blender scene using blender’s builtin palette system. These palettes can be appended into scenes just like mesh data or brushes, and you don’t need to have the image editor open in order to use them. The swatches are listed right below the color wheel. You just click the color you want from the list.
The issue is that when you click a color in the viewport, the eyedropper picks the gamma corrected color. I don’t think the same thing happens in the image editor.
EDIT: I just remembered something from an old tutorial. The difference in color isn’t because of gamma correction. The eyedropper samples the color with viewport shading added to it. You should get the actual color if you set the viewport shading to shadeless:
The image editor and eyedropper don’t matter here though. What you described can be done with blender’s palette system. It stores the exact color you set in the color picker. You can even paste hex values from other apps into the color picker and store it in the palette.
Just make sure there is at least one user for the data, or blender won’t save it with your project (same as with images and brushes).