We hope you will enjoy your stay here and help improve the Wiki -- all your help will be greatly appreciated! First off, why don't you try looking though these links as a guide to get started around here.
Before you start editing, read this FAQ to learn the basics of editing and how to personalize your userpage.
When you upload an image, keep in mind these rules, all of which you have broken in some manner today:
The first rule of uploading is: you do not talk about uploading.
The second rule of uploading is: you do not talk about uploading.
Sorry, I'll be serious now:
Crop out any black space around the image. Any art program on your computer can take care of this, even Paint.
Categorize your image.
Make sure the image's name makes sense. An image about Terra at the end of Dissidia should not be named "Terra/Tina", as that tells nothing about its content. "Terra Dissidia Ending" is much better.
Never upload duplicate files. If you uploaded an image named "Bartz ending", why then upload the same image with a slightly different name? Its pointless and now the wiki has two of the same image for no reason.
Add some kind of licencing information about the image, or it will be put up for deletion. I don't really agree with this rule, but one Admin does, so you have to watch.