Here is a workaround.

Open your image (or a screenshot you made) with Firefox.

file:///your_directory/your_image.png

In Firefox go to : Tools > Web Developer > Eyedropper

Left click on the color you want. It's copied in the clipboard.

For example : Hex: #497FC1

Here is a workaround.

Open your image, a screenshot you made or a web page with Firefox.

file:///your_directory/your_image.png

In Firefox go to : Tools > Web Developer > Eyedropper

Left click on the color you want. It's copied in the clipboard.

For example : Hex: #497FC1