|Photo by Mark Marek Photography|
You probably don't need the performer's permission (more on that later), but you would need permission from the owner of the copyright in the performer's photo. That could be the performer, but more likely it's the photographer, a stock photo business or a record label (or management).
Is it fair use? Your use of the pictures doesn't seem transformative, and whether your site sells tickets, or just operates as a virtual tote board of performer popularity, it's a commercial venture. These factors weigh against a finding of fair use.
But no matter ... You can get by without seeking permission by using public domain or Creative Commons images or promotional photos supplied by record labels or a band's management. Another pre-cleared source of imagery is Wikipedia where the provenance of each photo is provided by double-clicking on the Wiki picture (that's where we got the photo of Motörhead, above). If you're especially concerned about disputes, pay attention to any license limitations connected with the license -- for example crediting requirements.
Right of publicity. Aside from copyright, another legal concern is the right of publicity -- the legal right to prevent the unauthorized use of a person's image for purposes of endorsement. This shouldn't be an issue unless you are using a performer's name or image to promote your website, for example in banner ads.
Hassle factor. You may wonder -- after sorting through this legal maze -- how some sites get away without asking for permission when they use copyrighted photos. Three factors make that possible: (1) the owner isn't aware of the use; or (2) the owner doesn't consider the matter worth pursuing; or (3) the owner sees a benefit to the use and doesn't want to remove it.