Hans van der Meer wrote:

Searching information in the Wiki on the minimals tree the following page: http://wiki.contextgarden.net/ConTeXt_Minimals/Tree

did not render as expected, the thumnails are not showing; example:

Error creating thumbnail: convert: unable to open image `/var/www/contextgarden.net/contextwiki/images/4/46/P1030314.jpg': No such file or directory. convert: missing an image filename `/var/www/contextgarden.net/contextwiki/images/thumb/4/46/P1030314.jpg/300px-P1030314.jpg'.

Is there something amiss here?

Yes, the images appear to be lost.