Sure thing. It's actually pretty simple. When you click the edit button, you'll see on the right side bar that there's an edit summary section. Underneath it there's a section called "categories". When you hover on one of the category, say twitter users for the Spider-Man (Peter Parker) page, you'll see that once you hover across it, there's a trash bin looking sign. Just click that to remove the category.
But yeah, like what Annabell said, don't go removing categories unless their proven incorrect, but I'm assuming you're asking this because you added an incorrect category by accident.
Annabell, I'd like to inform you that Booster Beetle has apparently edited the following NavBoxes to the updated version: Template:Invincible Iron Man, Template:Mighty Thor, Template:Incredible Hulk, and Template:Ant-Man.
Looks like those last few still need some alphabetizing, anyway nobody's replied to my query about it on the Admin forum, so I'd give it to the end of the day just in case, then suppose it'll be fine to proceed.
Please stop manually adding categories such as vampires to the pages: Once the infobox template will be fixed, the categories will appear again because the modules and templates will recognize them in the infobox.
Please, whenever you upload a new image, be sure to do the following:
1) Don't forget licensing.
If you uploaded it through the Special:Upload function, make use of the "Licensing (Required)" dropdown feature before clicking "Upload File," so it can be legally displayed on the wiki.
If you uploaded it through the "Add a photo to this gallery" function on the bottom of galleries, you'll have to add the licensing manually. Go to the uploaded image and click "Edit," you'll see two rows of buttoms to insert templates or format functions. Click on the button that has a single photograph on it (found in the bottom row), and the template will be added. Be sure to fill in the "License" field with the respective license. Most common licenses are "Comic Single Panel," "Comic Cover," "TV Screenshot" and "Movie Screenshot." If the licensing you added is not valid, the image will still appear as unlicensed.
2) Whether the image template with licensing has been added automatically or has been inserted manually on the image, please be sure to fill in the respective fields there are, including "Source," "Universe," "Subject#," etc. to help sort it out.
I'm sorry that someone vandalized your page like that, in the future be sure to let an Admin know in case we miss seeing that something like that happened, so that we can address it further. It is clear they created the account with the express purpose of vandalism, so I've banned them indefinitely for harassing you.
You mean upload? If you need to upload a picture, firstly you have to name it by <Insert Name>_<Insert Comic Series>_<Insert Volume>_<Insert Issue No.> If your talking about using a picture that is already in the wiki just go to the photos section.