Any question answered...

Is the file upload feature also good "under the hood"?

Yes, in the sense that hosting images as attachments on lfgss is much more reliable than embedding them from some here today, gone tomorrow pic host, and you don't get tracked by the data miners or lose image visibility due to "improvements" at the host which make URIs volatile.

Obviously it would be even better if it actually worked first time most of the time on most browsers, but it's good once you've finally managed to find a combination of browser and phase of the moon which actually gets your pix onto the server 🙂