To add a Hover Zoom-In effect to a Divi image module, there are two steps to apply.

First of all, add an additional CSS class name to the module, for example:

zoom-in

 

Next, add the following code to the Custom CSS field under Dashboard / Theme Options / General Settings:

.zoom-in.et_pb_image:hover img,
.zoom-in .et_pb_image_wrap:hover img,
.zoom-in a:hover img {
    transform: scale(1.2); 
    transition: all 300ms 0s ease;
}

.zoom-in,
.zoom-in a {
    overflow: hidden;
}

.zoom-in.et_pb_image img,
.zoom-in .et_pb_image_wrap img,
.zoom-in a img {
    transition: all 1s 0s ease; 
}

 

 

Feel free to change the property values of the the animation code.