You can use a userscript manager like greasymonkey to inject a javascript snippet that will hide images in comments which have obvious urls to gifs and replace them with actual links or hide them

here an example snippet:

(() => {
  let timerID;
  function onChange() {
    Array.from(document.querySelectorAll('.comment-node img[src$=".gif"]')).forEach((e) => {
      const src = e.getAttribute('src');
      if (typeof src === 'string' && src.startsWith('http')) {
        e.setAttribute('src', '');
        const a = document.createElement('a');
        a.innerText = 'link to gif';
        a.href = src;
        e.parentNode.appendChild(a);
      }
    });
  }
  // if we have many mution events, wait until the site has settled
  function delayed_onChange() {
	  clearTimeout(timerID);
	  timerID = setTimeout(onChange, 500);
  }
  function init() {
	  // start observer
	  new MutationObserver(delayed_onChange).observe(document.body, {
	    attributes: false,
	    childList: true,
	    subtree: true,
	  });
	  delayed_onChange();
  }
  setTimeout(init, 500);
})();