We are aware of those potential issues you mention. Regular backup is part of our VPS plan at our provider. Now and then I do an extra backup of the entire server, just in case.
Apparently it is our chosen forum software that puts the attachments at the end of the posts. Other software behave differently, e.g. at our "sister" site, UVP.
I certainly did not mean to imply that inadequate backup problems would apply to this forum, for that I know that moderators are too careful to let that happen.
Congratulations with the duckweed book, look like quite an achievement! Interesting with the possibility of internal linking. However I wonder what happens if a user then forget to keep up the supporter membership? I have unintentionally had several longer (months) or shorter (days) lapses because the reminder ended up in in my spam folder (fixed now) or I was late because the reminder came so early that I forgot about it
. If the restriction is on the uploading side of the gallery, it should not be a problem though.
It is my observation over ≈13 years of looking at photo forums that it is much more likely that linked images will become unavailable at some point, as compared to forum-stored images. It is a pity that the forum software limits the text + photos layout possibilities...I understand why one would want to use externally linked files for that reason.
Yes, that would be the case as images are linked from all sorts of hosting sites. A lot of images disappeared when Flicker suddenly restricted how many images were allowed to be linked from from the free accounts. The possibility that free sites change their conditions of use should always be considered. Except for temporary system errors like the one that initiated this thread, I cannot recall pay sites like Smugmug and Zenfolio have caused broken links unless user induced or caused by buffering problems by the software of a forum. (I had a couple of single image cases on DPR that was driving me crazy; the originals were still available when clicking the "original" link though).
However I am always careful to link to original images resized by me because Zenfolio as mentioned above is notorious for now and then deleting the auto-generated resized previews, and regeneration of those on the fly is sometimes quite slow. They have good backup routines for the originals though. Both companies seem to be reasonably stable economically.
When this happened, I started thinking that it would be a good idea to now and then archive .pdf printouts of the part of forum threads where I have contributed images (might be harder with the monthly threads though), in case of need to restore them + plus also a mirror of the gallery where I keep the resized images, so that they are all in one place locally too. This would make it more easy to remember which image was used, and find a copy to restore from.