I've been using imgbox and imgbox-cli to upload images. I really love the snazzy built-in pict-rs uploader for Lemmy but I don't want to cause undue strain on my home instance.
They have ads on an image link's main page, but you can direct link without a problem. They don't offer a way to make donations or subscribe to a premium plan. They have a FAQ, but it doesn't mention monetary compensation. Not to say you should rely on them for eternity but it seems like they're a fine choice in the meantime.