We don't currently support associating a style and color by adding the variant color to the image name. We currently only support assocaiting an image with a color by adding the EAN code to the image name.
To associate an image of a style with it's color follow these steps:
Name the image by the EAN code, such as "7658943215637_1.png".
Next, add the position in which you want the image to show, you can upload up to 8 images per style. For example "7658943215637_1.png", "7658943215637_2.png", "7658943215637_3.png", "7658943215637_4.png", "7658943215637_5.png", "7658943215637_6.png", "7658943215637_7.png", "7658943215637_8.png".