Imaging systems having dual storage gate overflow capabilities

An image sensor pixel may include a photodiode that generates first charge for a first frame and second charge for a second frame, first and second storage gates coupled to the photodiode, a floating diffusion coupled to the first storage gate through a first transistor, a second transistor coupled to the second storage gate, and a capacitor coupled to the floating diffusion through a third transistor. The image sensor pixel may output image signals associated with the first charge generated by the photodiode for the first image frame while the photodiode concurrently generates the second charge for the second image frame. The second storage gate may be used to store overflow charge. Overflow charge for the second frame may be stored at the second storage gate while image signals associated with the first image frame are read out from capacitor and the floating diffusion.