Determining if file is valid image file

[Thomas Jollans]

On Thursday 02 August 2007, André wrote:
> On Aug 2, 11:14 am, André <andre.robe... at gmail.com> wrote:
> > Other than installing PIL, is there a "simple" way using Python only
> > to determine if a file is a valid image file?
> >
> > I'd be happy if I could at least identify valid images files for gif,
> > jpeg and png.   Pointers to existing modules or examples would be
> > appreciated.
> >
> > The reason why I'd prefer not using PIL is that I'd like to bundle
> > such a function/module in my app.
>
> I should have added: I'm interesting in validating the file *content*
> - not the filename :-)

The file name has nothing to do with the type :-P

A straightforward way you won't like: read the specs for all formats you're 
interested in and write the function yourself ;-)