CSS3 Linear gradient function (darker line between image and gradient)

So I am trying to make a linear gradient from an image with a solid color, however, there's a darker line visable where the color and gradient cross:

example:

The CSS:


.green-background {
    background: linear-gradient(to bottom, #3c7c3f, #ffffff);
    background: #3c7c3f;
    background: -webkit-linear-gradient(top, #3c7c3f, #ffffff);
    padding: 100px 0;
}

How to solve this?

Thank you!