What are your favourite add-ons/extensions on Firefox?

Got it, thanks for the patience :)

It makes the job easier than reverse searching image with Yandex (which is the best method I use).

Regarding reverse image search, this is the bookmarklet I use to lauch 5 different searches at once. On firefox you can set a keyword so I just type rev on the navbar on a tab with an image.

If the page has more than 1 images, it tries to print a number on each one so you can specify which one you want to search... but that feature doesn't work very well. Removing that, the script would be much more simpler.

(function() {
    var url;
    var args = '%s';
    var imgs = document.getElementsByTagName("img");
    var imgIdx = undefined;
    if (imgs.length == 0) return;
    if (imgs.length > 1) {
        if (args.length > 1) imgIdx = parseInt(args[1]);
        if (imgIdx === undefined || isNaN(imgIdx) || imgIdx < 1 || imgIdx > imgs.length) {
            numberImgs();
            imgIdx = parseInt(prompt(`There are ${imgs.length} images, select index:`, 1));
        }
        if (isNaN(imgIdx) || imgIdx < 1 || imgIdx > imgs.length) return;
        url = imgs[imgIdx - 1].src;
    } else {
        url = imgs[0].src;
    }
    if (!url) return;
    url = encodeURIComponent(url);
    window.open("https://saucenao.com/search.php?url=" + url);
    window.open("https://lens.google.com/uploadbyurl?url=" + url);
    window.open("https://www.bing.com/images/searchbyimage?cbir=sbi&imgurl=" + url);
    window.open("https://www.tineye.com/search?url=" + url);
    window.open("https://yandex.com/images/search?rpt=imageview&url=" + url);

    function numberImgs() {
        var imgs = document.getElementsByTagName("img");
        for (var img = 0; img < imgs.length; img++) {
            var parent = imgs[img].parentElement;
            if (!parent) continue;
            var numberDiv = document.createElement("div");
            numberDiv.innerHTML = 1 + img;
            numberDiv.className = "tmpImgNumberDiv";
            numberDiv.style.position = "absolute";
            numberDiv.style.padding = "2px 9px 2px 6px";
            numberDiv.style.background = "#f00";
            numberDiv.style.color = "#fff";
            numberDiv.style.zIndex = "9999";
            numberDiv.style.lineHeight = "normal";
            parent.prepend(numberDiv);
        }
        setTimeout(function() {
            var imgNumbers = document.getElementsByClassName("tmpImgNumberDiv");
            var idx = imgNumbers.length - 1;
            while (idx >= 0) {
                imgNumbers[idx].remove();
                idx--;
            }
        }, 5000);
    }
})();

One-liner:

javascript:(function() {var url;var args = '%s';var imgs = document.getElementsByTagName("img");var imgIdx = undefined;if (imgs.length == 0) return;if (imgs.length > 1) {if (args.length > 1) imgIdx = parseInt(args[1]);if (imgIdx === undefined || isNaN(imgIdx) || imgIdx < 1 || imgIdx > imgs.length) {numberImgs();imgIdx = parseInt(prompt(`There are ${imgs.length} images, select index:`, 1));}if (isNaN(imgIdx) || imgIdx < 1 || imgIdx > imgs.length) return;url = imgs[imgIdx - 1].src;} else {url = imgs[0].src;}if (!url) return;url = encodeURIComponent(url);window.open("https://saucenao.com/search.php?url=" + url);window.open("https://lens.google.com/uploadbyurl?url=" + url);window.open("https://www.bing.com/images/searchbyimage?cbir=sbi&imgurl=" + url);window.open("https://www.tineye.com/search?url=" + url);window.open("https://yandex.com/images/search?rpt=imageview&url=" + url);function numberImgs() {var imgs = document.getElementsByTagName("img");for (var img = 0; img < imgs.length; img++) {var parent = imgs[img].parentElement;if (!parent) continue;var numberDiv = document.createElement("div");numberDiv.innerHTML = 1 + img;numberDiv.className = "tmpImgNumberDiv";numberDiv.style.position = "absolute";numberDiv.style.padding = "2px 9px 2px 6px";numberDiv.style.background = "#f00";numberDiv.style.color = "#fff";numberDiv.style.zIndex = "9999";numberDiv.style.lineHeight = "normal";parent.prepend(numberDiv);}setTimeout(function() {var imgNumbers = document.getElementsByClassName("tmpImgNumberDiv");var idx = imgNumbers.length - 1;while (idx >= 0) {imgNumbers[idx].remove();idx--;}}, 5000);}})();

The 5 searches it launches are (replacing XXXX with the image URL):

• Google: https://lens.google.com/uploadbyurl?url=XXXX
• Bing: https://www.bing.com/images/searchbyimage?cbir=sbi&imgurl=XXXX
• TinEye: https://www.tineye.com/search?url=XXXX
• Yandex: https://yandex.com/images/search?rpt=imageview&url=XXXX
• SauceNAO: https://saucenao.com/search.php?url=XXXX