A couple of tools to help finding the original sources:
- dessant/search-by-image: Browser extension for reverse image search
- SauceNAO's "Image Search Options" addon: Firefox - Chrome
- Reverse image search engine URLs (replace XXX 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
Also, thanks to @Blaze@discuss.tchncs.de and @Stamets@startrek.website for the mentions :).