It would have less of an effect on thrust than you would probably imagine. The biggest concern here would be the amount of material lost/moved and the resulting balance of the blade. Nicked, chipped and cracked props can cause severe strain to bearings and crankshafts (aircraft cranks are usually hollow to supply oil to the prop pitch mechanism).

Jettisoning the blade would be the last thing you'd want to do, unless you could somehow lose the two opposing blades and keep everything perfectly in balance (and keep all of your engine oil from hemorrhaging out of the prop hub). You have to consider that when that blade is at speed there is a centrifugal force on the hub equal to the weight of several cars. If you throw a blade you suddenly have an imbalance of several tons, alternately torquing your engine up, down, left and right several dozens of times per second. I've heard stories, and seen pictures (although my two hour search failed to find the examples I remember) where guys have lost an entire blade (or half of one due to a crack) in flight and the subsequent vibrations literally tore the engine from its mounts. In one case the cowling, and its dzus fasteners which held it together, were all that was holding the engine in the airframe. In a couple other cases, the engine completely separated from the aircraft, resulting in the center of mass shifting aft far beyond the CG limits and the aircraft spiraled tail-first, uncontrolled into the ground

TL;DR - In the case of that picture, probably nothing happened beyond a vibration and excessive crankshaft bearing wear, but had that blade tip been completely shot off, it could've been a lot worse.