An image sensor includes a first photodiode with associated first sense node and a second photodiode with associated second sense node. A first transistor has its control node coupled to the first sense node and a second transistor has its control node coupled to the second sense node. The conduction paths (for example, source-drain paths) of the first and second transistors are coupled in series between first and second column lines associated with a column of the image sensor array. Switches control connection of the first and second column lines in two modes: one mode where a voltage is applied to the first column line and data from one of the photodiodes is read out by the second column line; and another mode where a voltage is applied to the second column line and data from the other of the photodiodes is read out by the first column line.