There are two bands with this name:
These are photos from concerts where Warm Jets played, so they may be of other bands that played the concert as well.
Reading Festival 1998 Aug 28 - 30, 1998 Reading, England, United Kingdom Uploaded by Andy Goymer
T In The Park 1998 Jul 11 - 12, 1998 Kinross, Scotland, United Kingdom Uploaded by John Collins