Summit also has the setting to use imgur instead in cases where the instance upload rules are too strict.

Voyager can do it too, via PWA even. Don’t even need to press the upload button, simply copy and paste the image, it gets uploaded and included in the comment automatically.

I think with file size limits it's not really so bad for cost. Lemmynsfw proves that.

Add image hosting with an ephemeral approach like 4chan, where posts older than a day get little interaction and low-quality content is deleted after a month. This keeps a long-term archive of high-quality content without clutter.

I don't think that's the issue since you can upload images for an image post. It's more the effort of doing file uploads from a dynamically inserted part of the page (the reply box). I don't know enough Javascript to be able to do that.

I think on order for this to happen, we (the collective we) would need to donate far more than current levels.