Changing color of color stops with color selector, eyedropper tool

I am tying to change the color of my gradient fill to the color of the blue on the ear tag.  But when i click on the blue i get nothing, it moves to white.  I thought that i could use the color selector to pick any color from my photo, to use as a color in my gradient.  I've seen videos that have show it.  What am i doing wrong.  I'm a newbie so maybe im missing something minor.  The photo above is a screen shot of my editor windows.