Performance issues with FTP uploads to remote server?

[eluser]skunkbad[/eluser]
I've heard that it is more secure to serve your website's images from another domain. I don't think it has to be on another server, but if FTP is the only way to get it there, then I think it's a good thing. Take for example an image that has been altered to include PHP code. I've done this with a .gif image, and when served the PHP will run. If you allow somebody to upload images, they could add PHP inside it, and it would run when the image is served, which is bad. Have you ever done this? Yes, it is quite mischievous. Do you want people to be able to run PHP code on your server? Probably not.

I do a lot of file uploads that get instantly FTPd to another server. There is a performance issue, because you never really know the status of the other server, and the condition of the connection between the two servers is never really known. You need to plan to have a fallback, where the upload is temporarily stored on the first server should the FTP connection fail.