css: avoid image hover first time blinking

Question

I have an anchor that changes its background image when hovered with a class class-btn that contains a background-image.

When hovered, it

Answer 1

Just change the size of the background image, instead of the source of it! So...

a.class-btn {
    background-image: url('path/to/image-hovered.jpg');
    background-size: 0;
}
a.class-btn:hover {
    background-size: auto;
}