Would a non-breaking space as the title work?
>
> Nope, because, the space for the title would still be there and I want to
put a full frame image


> Otherwise, you can define a dummy string, i.e. "NOTITLE", use that as
> the headline. Then, with the appropriate filter, you can change
> \begin{frame}[...]{NOTITLE} into \begin{frame}[...]{}.
>
>
> But this one will work and is esay enough. Thanks.

Fabrice