1. An imaging system for a vehicle comprising: an imaging array sensor comprising a plurality of photo-sensing pixels, said imaging array sensor being positioned at the vehicle and having a field of view exteriorly of the vehicle, said imaging array sensor being operable to capture an image of a scene occurring exteriorly of the vehicle, said captured image comprising an image data set representative of the exterior scene; a control for processing said captured image, said control algorithmically processing said image data set to a reduced image data set of said image data set, said control processing said reduced image data set to extract information from said reduced image data set, said control selecting said reduced image data set based on a steering angle of the vehicle; wherein said control processes said image data set to determine a location of a portion of the equipped vehicle relative to said imaging array sensor as mounted at the vehicle, and wherein said control establishes a calibration for said imaging array sensor that, responsive to processing of said image data set to determine the location of the portion of the equipped vehicle, verifies that said imaging array sensor is mounted at the vehicle within a desired tolerance; and wherein said control, responsive to a determination that said imaging array sensor is not mounted and aligned within said desired tolerance, is operable to adjust at least one of said image data set and said image processing to at least partially compensate for the detected misalignment of said imaging array sensor.