JSFiddle - React, Tailwind, and code Playground
HTML
<div id="imageDiv">
<a id="testA">
<img alt="" src "" id="img1">
<img alt="" src "" id="img2">
<img alt="" src "" id="img3">
<img alt="" src "" id="img4">
<img alt="" src "" id="img5">
</a>
<img alt="" src "" id="img6">
</div>
JavaScript
function areSiblings(e1, e2){
return $(e1).parent().children().is($(e2));
};
console.log(areSiblings("#img1", "#img3"));
console.log(areSiblings("#img2", "#img5"));
console.log(areSiblings("#img1", "#img6"));