The image sensor has a plurality of pixels arranged in rows and columns to
form a pixel array, each pixel column having a column bitline. The image
sensor includes a column readout for each column bitline and at least one
additional column readout. The additional column readout may be
selectively connected to one of the column bitlines. In one embodiment, a
defective column readout can be isolated and the additional column
readout used as a replacement.