The problem wasn't where the content came from. The problem was the quality of the content provided on the page. The page only had two paragraphs of content, one of which was a poorly translated outline for the story. Since I've learnt from experience (while editing the v6 page) that whatever you are using to translate the outlines was creating far too many significant errors, I would have had to remove the paragraph due to low quality and since I had an exam to get to, I could make my own translation of it. Hence, that would have left the page at one paragraph with no other content on it. However, according to our guidelines, a page must have at least two paragraphs of content (or one paragraph of text + one image) to meet at least the bare minimum content requirements for articles on the wiki.
Thus, I decided to delete the page and remake it later on when I had a break from my exams and could provide a proper translation for the outline of the volume.
Basically, when uploading an image, a file needs to:
1.) Be in a .png format in possible highest quality.
2.) Have a proper and specific name.
3.) Be correctly sourced.
4.) Be accordingly categorized.
I strongly advise reading above guide or, if you still feel confused, feel free to ask me, or any other user/editor. Alternatively, you can join our Discord channel https://discordapp.com/invite/PRUcDpM, where we can directly help you getting used to editing SAO Wiki.