As only administrators can upload this file, and it can only be uploaded through the theme designer, authorship doesn't always show through.
The first version uploaded to this filename (featuring Tedd sampling the icing) was by User:Nixonma and originally uploaded to File:Wiki wide.PNG in a higher resolution. It was copied over by User:Thorenn, hence the uploader credit.
The second (featuring an artist-Sarah sprite) was uploaded by User:Thorenn. No other information on authorship is known.
The third (featuring Tedd, derived from the All Male Wallpaper but with hair colour changed to his natural purple) was created by User:HarJIT, using the previous revisions as a basis, and originally uploaded to File:Wiki-wordmark-proposed.png for the purpose of proposing it. It was instated/copied over by User:Hkmaly, hence the uploader credit.