Pleiades is the highest resolution civilian earth observing system ever developed in Europe. This imagery programme is conducted by the French National Space Agency, CNES. It will operate in 2008-2009 two agile satellites designed to provide optical images to civilian and defence users. Images will be simultaneously acquired in Panchromatic (PA) and multispectral (XS) mode, which allows, in Nadir acquisition condition, to deliver 20 km wide, false or natural colored scenes with a 70 cm ground sampling distance after PA+XS fusion. Imaging capabilities have been highly optimized in order to acquire along-track mosaics, stereo pairs and triplets, and multi-targets. To fulfill the operational requirements and ensure quick access to information, ground processing has to automatically perform the radiometrical and geometrical corrections. Since ground processing capabilities have been taken into account very early in the programme development, it has been possible to relax some costly on-board components requirements, in order to achieve a cost effective on-board/ground compromise. Starting from an overview of the system characteristics, this paper deals with the image products definition (raw level, perfect sensor, orthoimage and along-track orthomosaics), and the main processing steps. It shows how each system performance is a result of the satellite performance followed by an appropriate ground processing. Finally, it focuses on the radiometrical performances of final products which are intimately linked to the following processing steps : radiometrical corrections, PA restoration, image resampling and PAN-sharpening.