Bugfixes for flags

[Liblor]

Using args.config to reference to the config flag led to to an AttributeError (Python 3.6.1, Linux).

According to line 35 and 37 the image flag should be called "picture".

[abertschi]

Thanks for looking at the code. Unfortunately, it's super bleeding edge and I already fixed these issues.

Most features are now done except the dedicated --accounts argument. which is optional tho. I think we should use a better approach to print error messages. I just use print but we should rather use a logging framework and perhaps throw custom exception on input validation which we catch and just print the exception message instead