I didn't have a clue on the first one - wouldn't know where to start, but Black Flag was easy to identify the band then work through the covers to Slip It, and yes the last two are both High Voltage. The original Australian release, then the American (?) cover. The British version had a fab cartoon cover of Bon & Angus:

The Australian release has a different tracklisting, because it was combined with debut 'TNT' for the international versions.