authentication of documents

Q1> can following kind of documents and its sender be authenticated by legal system:

--emails  - NO

--gtalk chat - Yes But I dont think court will accpet it

Q2> can a digitally taken photo also be authenticated ? its depends on situtaion let us know the situation

Q3> If some one is trying to hack the email password then a auto generated emai is send to secondar email address. Can a hacker be trced by this email ?

If it contain ip address of hacker who want to log

Like

"

Dear Customer

At date dd-mmm-yyyy a wrong login was attempted by this ip xx.xxx.xxx.xxx

"

Thank you