Around the time Pearl Jam was recording the follow up to their hugely successful debut, Ten, the members were involved in a number of struggles with the powers that be, most famously singer Eddie Vedder taking on Ticketmaster. In addition to these real conflicts, the media was painting a contest between Pearl Jam and fellow Seattle-ites Nirvana, which Pearl Jam has vocally said was a complete fabrication. It is for these reasons that they titled their sophomore effort Vs. (initially Five Against One for similar reasons).
The cover art, a black and white photograph of a sheep taken by bassist Jeff Ament, is representative of the way the band felt at the time. While they were grappling against things they found unjust with all their might, they still often felt like they were trapped in a cage.
On a personal level, I was 12 when Vs. came out, and the older guys that I hung around with at the time were all huge Pearl Jam fans, and they were among the 1.3 million people that purchased copies the first week the record was out. Seeing copies of this CD going around, I couldn't help but be drawn to this powerful image. It also didn't hurt that some of the best music ever recorded also happened to be included on the bright orange disc.