Photo uploads not working – 404s instead of images

Hey all!

I’m working on a staging copy of my website to get everything in order before I send it live. However, I’m having a lot of problems with uploading photos.

On my current live site, images are uploading fine. On my staging site, which is a copy of my original, just now very modified page-wise from the current live version, no newly uploaded photos will load. As soon as I hit publish, they disappear. I talked to my hosting company, and they said the following (minus personal info):

“I checked the staging using Chrome’s Firebug tool and noticed that the application is trying to load resources from non-existent urls:

[url is posted in private content]

As a result returns a 404 status (not found) since such content does not exist on it.

I was not able to find references to the URL in question in your staging website’s database which most likely means this is a hardcoded URL somewhere in your application’s code.

Such custom configurations will need to be manually altered by a professional developer with in-depth knowledge of WordPress code.”

My site is a photo-heavy site, and I need the photos to work before I can push it to the live version. I’m very confused as to what is happening, and I need advice on what to do so that I can get my images up so I don’t have to redo hundreds of photos when it’s live – or just the fact that I’m unsure they’ll still work when it IS live. The images that WILL load on my staging site were migrated over from the current live site, before any of this was an issue. I have not touched any code at all, and not even touched the galleries except to (attempt) to upload photos. My theme is up to date. Help, please!