Change permissions of a file in the uploads folder

I want to replace an image in the uploads folder manually via FTP.

Can I ask why?

I have an animated GIF and it does not work as a featured image because of the resizing by both my theme and wordpress itself. I tried a GIF resizing plugin but the image quality was really bad…
I figured if I just replace the file the whole problem is solved.

I’m not sure that is going to work…

Why wouldn’t it? It would have the exact same filename and even the size is the same. Only difference is one animates and the other doesn’t?

Do you know which of the 4 potential files you need to replace?

Yes, it’s just one. I have opened it in a new tab from my homepage so I know the exact file naming…

If you are having problems with FTP, you need to speak to your hosts about it. That’s well outside of WordPress’ control.

But I am the host?
I have a VPS…

I think all permissions are fine. I mean, 644 for files in uploads is okay right?
I just can’t change them?

Have you looked at the possibility that this could be a folder/file ownership issue?

All folders on top have 755? (month / year / uploads / wp-content)

I’m sorry but we cannot help you troubleshoot your own server here. Perhaps you could try asking on a forum dedicated to your VPS type?

But it happened after I moved the wordpress folder to another directory. I did all preparations according to the wiki on www.remarpro.com. I used a plugin to make the media files working again and now I can’t change permissions… ??