That neck joint looks fine.

First thing is to wind the adjustment up on the bridge saddles till you can play it. It's a good idea to get one of these:



They are not expensive and are very useful. I'd normally aim for about about 1.5mm at the 12th fret, but anywhere up to 2 on the bass E is acceptable, generally I ball park it and then fine tune it over a couple of days.

Then you would want to check the relief with one of these.



I just made mine with a bit of alloy from the big green shed and a file. I used another guitar to mark the fret locations then just filed them out.

This will let you see what kind of truss rod adjustment you need to do. If the neck curves away from the middle of the ruler, you need to tighten the truss rod. Looking down the neck toward the body, you need to turn it clock-wise. Loosen the strings, do about 1/4 of a turn, tune it, the let it sit over night, recheck and see if it needs more or not.

If that doesn't improve things get back to us and we'll go from there.