Ok, I think I understand now. The explanation helped. You can definitely do this for a product that has different options. Using your analogy of a coat with multiple color options is correct. If in the product update page you selected the green color option any updates you make would be specific to that variation including the images descriptions and other product properties.
The only exception to this would be if you checked the box to update all of the entries with those values, then they would be applied across all the variations of that product.
What the user will experience on the front end is the default options for the product, then if they update the color to green it will show them the image you uploaded for that color option, presumably a green coat.