What to use in if statement to consider the first image

[BM136]

Hi,

My goal is to add a border on all product images except the first one.

What should I add in the if statement to consider the index of image?

Note, We don't have options, and I was able to do it for thumbnails, since thumbnails added by a for loop, I used forloop index. but I want to apply it on big image too.

Thanks in advance 🙂