Thumb was a German Rapcore band formed in November 1993 in Gütersloh. According to the band's official website they appear to have ceased in 2005 into various side projects; Steffen has joined H-Blockx, Jens is in Taetowier Studio, Jan-Hendrik is in Hudson, Claus is in Alternative Allstars and Axel is in Waterdown.
These are photos from concerts where Thumb played, so they may be of other bands that played the concert as well.
Bizarre Festival 1997 Jul 15, 1997 Cologne, North Rhine-Westphalia, Germany Uploaded by Daniel Fischer
Hurricane Festival 1997 Jun 21 - 22, 1997 Scheeßel, Lower Saxony, Germany Uploaded by Torsten S.
Rock am Ring 1997 May 16 - 18, 1997 Nürburg, Rheinland-Pfalz, Germany Uploaded by Sandra Gartenfreund