The method I've settled on takes a bit of work to put together. First, I upload PNGs to catbox.moe. This preserves metadata so someone can feed the image into the A1111 PNG Info tab, or by copying the url to https://pngchunk.com.
Next, I upload JPG copies here. That gives me the lemmynsfw hosted url and builds the gallery. Then I put them both together using markdown so that the image gallery is also links to the PNGs. The final format looks like this:
[![](https://lemmynsfw.com/pictrs/image/59c7f6e6-de70-4354-937b-5b82b67fc195.webp)][1]
[![](https://lemmynsfw.com/pictrs/image/88b14211-4464-4cd2-bb28-05e781dd5fc8.webp)][2]
[![](https://lemmynsfw.com/pictrs/image/bf3a69bb-d0f9-4691-b95e-6794880bbc86.webp)][3]
[1]: https://files.catbox.moe/5dsqza.png
[2]: https://files.catbox.moe/dljkxc.png
[3]: https://files.catbox.moe/kcqguv.png
This seems to work well. The only hiccup is that I need to include the first image twice, once in the post body so it shows in the gallery, and once as the post header image. That works okay in the browser, but some lemmy mobile apps show it as a duplicate.
Here's the final result: https://lemmynsfw.com/post/1372540
Lookin good! I was just perusing the metadata and got a chuckle out of "wearing a light grey shaved smooth vagina."