Image zoom on hover

Hello 🙂 

I'd like to have an effect on a few images in a section of a page on my website. But I can't find the error in the code found on youtube tutorials. 

Here's a screenshot of the code: 

Thanks in advance for your help 😄

You've got the closing square bracket from the section ID in the wrong place, move it as here:

It doesn't work like this but i found an other code and it's working actually with : 

And, if i want to have this effect on just 4 images of this section, do i need to code for each images ?