image.src is a blob so you can extract the data by fetching it e.g. const buffer = await (await fetch(image.src)).arrayBuffer Though this does not solve all the downstream issues. Let me know if you want me to collaborate on this.

Ah cheers. These serverless cells are pretty cool. I'm having a bit of trouble debugging them though. I only published so I could get the endpoints public and I could start playing around. I'll have some more time in a couple hours where I'll take a stab at this again. But if it's an easy fix let me know! Thanks

if you print the text when the response is not 200 you will see the response payload said "res.send() requires an arg" (i.e. the arrayBuffer arg was undefined) but you can also see the full logs at https://observablehq.com/@endpointservices/logs if you have a google account. The onboarding is a bit rubbish but the logs are pretty low latency and usually helpful.

Cool, got it working. Scratched my head over mimetype issues. I'll probably do some clean up later. Thanks for the pointers!