Yes, it is in theory possible to see what images are expired and removed with the right debug level, and enough disk space. But it is not straight job.
I think, it would be better to dump the output from bpimagelist into text file(s) at various point in times, to captur expiration information before the image actual get expired.
Or trust Netbackup, if a backup image isn't available, the backup is not taken or it's expired.
My 2 cents....
You can use nbauditreport command to check this out....
here is from my test made just now
root on server:/root $ bpexpdate -backupid server_1686044078 -d 0 -force
root on server:/root $ nbauditreport |grep -i expir
06/06/2023 04:35:25 root@server Catalog Image 'server_1686044078' expired.
Not 100% sure it work when Netbackup expire the image. The manual says for 8.1
Internally initiated actions.
NetBackup-initiated internal actions are not audited. For example, the scheduled deletion of expired images, scheduled backups, or periodic image database cleanup is not audited.