See attachment. From the image can I conclude that, below the saturation current the P.E current is proportional to the incident frequency but above the saturation current it is independent on frequency ?

Photoelectric current is dependent upon the number of photoelectrons knocked out of the plate. That depends on the number of photons incident on the plate.
If the frequency of the photons is higher than the threshold, you will observe current. This may not be equal to the saturation current because the electron may get knocked off but not reach the other end of the tube. To make them reach the other end of the tube, you have to apply a potential to pull all the photoelectrons to the other plate.
Hope that answers your doubt.
Comment if you have further questions