All database objects will be in the image and you will not miss any data if you take an offline backup (as your syntax indicates). If you take an online backup, you can use the "include logs" keyword to include the logs that were active during the online backup and that are needed to a do a restore.
The only thing that is not backed up is the instance configuration and db2set environment variables. You can print those with the following commands:
db2 get dbm cfg
Depending on how you restore the database backup (as a new database or to replace an exisiting database with the same name) some db config parameters will not be replaced by the restore, so to capture those you can use this command:
db2 get db cfg for <db-name>
M. A. Feldman
IBM Certified DBA on DB2 for Linux, UNIX, and Windows
IBM Certified DBA on DB2 for z/OS and OS/390