Moving Photos without Resizing?

Hi all,

I've some big silde scans im my intranet gallery (on a very slow server). That it takes time to upload them because they have to resized and the tumbnails have to be generated is okay for me.

But if moving them around, I want to avoid the resizing and thumbnail generation. For me it would be fine if all my pics have same thumbnail size and the same intermediate pic size.

Any suggestion?