Many people put in too much information when writing a biography - or at least, too much of the wrong kind of information !!
A Songwriters biography needs to be short & sweet. Photo's aren't necessary unless you are a performing artist, but they certainly never hurt.
Don't mention what grades you got at school - nobody cares. Definitely mention any relevant achievements, such as songs being released or published, co-writing with a "name" writer, etc.
Under no circumstances make any wild claims such as having written hundreds of songs: if you've really written that many songs and are still unsuccessful, it does rather suggest you're doing something wrong in your writing. Also, don't claim to be able to write every genre possible. It's virtually impossible to write them all well.