(Ninjaed by a nicely succinct alternate suggestion.
)
It has been known. There are prior threads about it that talk about how it happens (probably something to do with the artefact being created as a concept, then it considers the adornments and in amongst the choice of things-to-be-adorn-on-it is the list of artefacts created, to which itself has just been added) so it's not unknown and not a 'bug' so much as an interesting feature.
As regards posting images, this forum doesn't support image-uploads to itself (if that's what you're unsure about, some fora do and some fora don't) but you can embed image-links to images you have hosted elsewhere by
[img]image url here[/img] as the BBCode, with the picture-frame icon to the far left of the lower buttons (just to the left of the more-obvious 'globe' one that's for URL links), above the message-writing pane, as a handy click to get. If you have a favourite third-party image-hoster that you're already familiar with then use that, though there's
Dwarf Fortress File Depot (a parallel but separate resource) that maybe you'd find useful for specifically DF-related images? Not sure, but you can check it out yourself.
If it's the act of taking the screenshot, then depends on your system
exactly which ways you can do it, but I wouldn't want to presume that this is where you're stuck, anyway. But do ask for more help for any bit I haven't explained enough for you and I/someone else can do a better job.
And welcome! I hope you enjoy
failure the myriad joys of Fortressing!