Electronic devices may include image sensors having image pixel arrays with image pixels arranged in pixel rows and pixel columns. Each pixel column may be coupled to a column line having column readout circuitry and column power control circuitry that selectively enables or disables the column readout circuitry for various column lines. The column power control circuitry and the column readout circuitry may be coupled to column decoder circuitry. The column decoder circuitry may provide a column address signals to the power control and the readout circuitry. The power control circuitry may enable only column lines for which column addresses have been received.