Can't see photos from previous Time Machine backup

Here is my issue:

1. I had two MacBook Pros (one old, one new).
2. I bought an external hard drive.
3. I backed up both the old and the new MacBook.
4. I wiped and sold my old MacBook.
5. I opened the backup of the old MacBook on the external hard drive in an effort to find my old photos.
6. On the external drive, I went to Backups.backupdb > Users > Pictures.
7. On the Pictures icon I see a red "caution" type icon.
8. I click on the folder and get a popup that says, "The folder pictures can't be opened because you don't have permission to see its contents."

How do I access all my photos that are in this "locked" folder?

Thanks!!

Jim