how to change the Logo?

I have upload to the router a logo.gif to
user-manager/img/logo.gif

also change the location in the setting
/um/img/Logo.gif

but I can’t see the image
I have also try to create a new folder in the router
called um/img/Logo.gif

and still can’t see the image

what is wrong?

maybe image size ?

Thanks ,

yes maybe the size , please send me the required photo and i ll resize it to the required one

But what is the proper or required size?

I have change the size to smaller - and now I can see the it
strange.

Thanks ,