Is there a way to filter by aspect ratio on Google Image Search? I need to find images with a ratio of 2:1 but Google only offers me some generic terms like "wide".
You can search by general aspect ratio or exact size, but there is no way to search by exact aspect ratio.
You can however set the size of one dimension by typing, eg.
banana 1080, so if you know one dimension you may be able to combine that with the rough aspect ratio to get pictures that mostly match your criteria.
Though not as specific as you're asking for, the advance search does include an aspect ratio option. You only get to choose between any, square, wide, tall, and panoramic, but that could still help: