An image sensor with an array of image sensor pixels is provided. The array may be configured to operate in a rolling shutter operation mode or a global shutter operation mode. Each pixel may include body bias control circuitry that generates a body bias control signal. Each pixel may include a photodiode having a p-type terminal that receives the body bias control signal. The body bias control signal may be adjusted to a negative voltage level during the pixel operation to improve the pixel full-well capacity. The body bias control signal may be adjusted to a negative voltage level during reset and charge transfer operations and may be adjusted to a ground voltage level during readout and charge accumulation operations. During rolling shutter operation mode, different body bias control circuits may be used to bias respective rows of pixels within the array.