Mouse over opacity on picture

Hi,

I would like to add the function “mouse over opacity on picture”. I found some input in the public threads, one recommending like follows:

1. Edit the Page Builder row in question, click the Attributes tab and enter a CSS class name in there: image-hover

2. Then to go Appearance > Custom CSS and target that:

.image-hover img:hover {
opacity: 0.5;
}

I tried, but unfortunately nothing happens.

Maybe you can give me another advice.

Thanks in advance …

Warmly from Vienna,

Birgit