Ransomware attackers specifically target and attempt to destroy backup systems to increase the probability of payment. Hardening your system is critical. Please ensure you have reviewed your platform security using the Security Hardening Checklist
About NetBackup image files — NetBackup 8.2 | Cohesity Documentation
About NetBackup image files
Each image file is an ASCII file, generally less than 1 kilobyte in size. An image file contains only backup set summary information. For example, the backup ID, the backup type, the expiration date, fragment information, and disaster recovery information.