Update the texture of ShaderMaterial on hover with effects

Hi members!
I have a CircleGeometry with ShaderMaterial. And I’m passing two colors to uniforms for creating a gradient color using a simple fragment shader code like this:

uniform vec3 color1;
uniform vec3 color2;

varying vec2 vUv;

void main(){

Note: I’m setting the vUv value inside my vertex shader.
And this is the result (online demo):

Now, I want when the user hovers on these objects, shows the background image for these objects with a zoom-in effect for example. How can I achieve that?