Hehe, not quite "all" of them. I currently manage about 70 gaming wikis.
Some are very active, and some are mostly derelict, with little to no editors. - Sitb(Message wall / Talk page) 11:41, November 3, 2019 (UTC)
I presume you're referring to jtoh-tower-sequence.fandom.com, a wiki you created yourself back in July? No, I've never heard of it until just now. You're the wiki's only notable contributor though, so it's likely that you're one of just a few people who know about that wiki's existence. - Sitb(Message wall / Talk page) 12:39, November 3, 2019 (UTC)
I am not the manager of your wiki. Your wiki has no Wiki Manager. As the founder of that wiki, you should personally submit a wiki closure request to Fandom staff via a ticket. Please visit this link and follow the steps to have your wiki closed. - Sitb(Message wall / Talk page) 12:57, November 3, 2019 (UTC)
Fandom staff already know your email (you used it to create your Fandom account). Technically, staff can also see the various IP addresses you've edited with as well. However, unless you do a bunch of vandalism or breach other aspects of Fandom's terms of service, no one ever has a reason (or interest) in looking up that information. - Sitb(Message wall / Talk page) 13:05, November 3, 2019 (UTC)
Help:Background explains the steps you need to follow to create a custom background, including the appropriate dimensions that are required. It would make more sense for you to read the instructions there, rather than me copy-pasting them here. - Sitb(Message wall / Talk page) 13:25, November 3, 2019 (UTC)
Are you asking how to format/size an image you have on your computer so it is acceptable as a wiki background? Or looking for the theme designer tool, which is used to customize various ways a wiki looks overall? - Sitb(Message wall / Talk page) 02:01, November 4, 2019 (UTC)