404 error page
404 error page “Page not found” is the error page displayed whenever someone asks for a page that’s simply not available on your site. 404 means the file is not found. If you already uploaded the file, then either the name is spelled wrong or it is in the wrong folder.
How to find the correct spelling and folder.
Other Possibilities
You may get 404 for images because you have Hot Link Protection turned on and the domain is not on the list.
Else, if you go to http://ip/~username/ and get a 404 error, one reason might be that you inadvertently deleted your public_html folder, or the entire account may need to be recreated.