It stumps me - I've already checked the usual culprits, and everything seems to be in order. I've updated the shop system and checked the database... nothing. So I will have to add the things without pictures for now, and hope I can solve the problem soon.
Meanwhile, have some more pictures taken at Freienfels, where I did an outdoor test of the oil light wicks in a medieval-style glass lamp:
Not so with the floaters - as long as there is oil to burn, it burns quietly and like a charm. Towards the very end, there are some quiet sputtering noises, warning you that the lamp will soon run out of fuel, so you have time to refill with some oil, or you can just wait until it has burned itself out.
We had the lamp hanging outside, and with the water level low enough, it was even relatively wind-resistant. I really enjoyed having it hang there, and it was giving a lot of light all around: the beauty of the glass lamp is that it's also illuminating the things right below the lamp, as opposed to a lantern or candle-holder. I will definitely use this lamp a lot more often in the future!