He is a photo-journalist and documentary photographer. Since 1992 he has worked for the Axel Springer Prague publishing house (previously he worked for Automedia and the magazines – Svět motorů (World of Motors), Autotip, Autoexklusive, F-1 Racing, and Autoprofi).
He belongs among the acclaimed sports photographers and his work focuses mainly on automotive sports and specifically on shots of cars and Formula 1 races. He is the only Czech photographer to hold accreditation for these races.
In his free time work his interest has shifted from initial, scene-like snapshots to documentary photography, where he focuses foremost on a new lifestyle. He gained attention for his collections Hypermarkets / Hypermarkety (2000), Small Town / Městečka (2001-2002), and Mobiles / Mobily (2003). He creates colour shots, in which he combines natural light and use of flash placed apart from the camera and usually covered with a colour filter. This technique allows him to accentuate a specific part of the picture, emphasise it, and thanks to the technique mock the captured scene.
Lendelová, Lucia – Pospěch, Tomáš – Rišlinková, Helena: Česká a slovenská fotografie 80. a 90. let 20. století. Katalog výstavy, Muzeum umění, Olomouc 2002.
Jiří Křenek. (Úvodní text Vladimír Birgus), Kant, Praha 2004.
Formule 1 ve fotografických obrazech Jiřího Křenka, GDK, Praha 2006.
Birgus, Vladimír: Jiří Křenek – Hypermarkety. Fotografie Magazín, 2001, č. 2, s. 10 – 14.
Birgus, Vladimír: Jiří Křenek. Kwartalnik Fotografia, 2004, č. 16, s. 16 – 21.