Some of that action height is because the nut slots are high, and that brings the action up. I's fit a capo on the first fret (or tape the strings down well if you've no capo) to give a more realistic impression.
As Trevor says, you need to check the neck relief as well. I'd start off with the neck flat, then the tension of the two strings fitted will add in probably just enough relief to make it like it would be after being set up.
The bridge looks like its probably as low an adjustable type as you are going to get, so if the action still looks high, then you will need to adjust the neck angle.
I'd first check that the bottom of the heel and the floor of the neck pocket are about as level as they can be. It doesn't take much for a bump or lump near the neck end to angle the neck downwards.
After that, it's definitely down to adjusting the neck angle.
Looking at the pictures the neck heel tenon is roughly 1/3 of the distance from the neck end of the body to the bridge. So if you raise the body end of the tenon up by 1mm, the strings will be approx. 3mm higher at the bridge if run flat along the neck.
If you can run a straight edge along the neck to the bridge and work out how much the strings will need to move to come up to the saddles, then you should be able to divide that height by 3 to work out how much the end of the tenon needs to be raised by.
The safest way to do this is to make or buy a shim the length of the heel tenon. Not the easiest thing to make as it will be very thin. Unless you feel confident about cutting a thin wedge from a solid block of wood, its easiest to use two or three of pieces of standard thin veneer (0.6-0.7mm thick) and sand it down (using double sided tape to hold things down is recommended). I'd use maple veneer if possible as it's pretty strong and will match the neck wood.
You could make a basic jig up like drawn below.
If you want a shim that is 1mm high on one end, then stick a 2mm high block on some wood double the length of the shim away from the edge (block is always 2x the required shim end height).
Use double sided tape to stick the basic shim to the wood so it touches the edge of the wood.
Use double sided tape to stick some sandpaper on another bit of flat wood, so that you can run it back and forth and sand the shim down, but don't put the sandpaper on all the length as you don't want to sand the 2mm block down as well!
Sand away, and when the sandpaper reaches the end of the bottom block of wood, you're done.
This is going to leave a very thin and fragile shim, so you may want to make it one layer of veneer thicker throughout. In this case stick a layer of veneer on or under the 2mm block, and stop sanding when there is just one layer of veneer left at the end of the bottom block. Marking the wood you want to sand away is recommended, to help stop over-sanding.
The shim can then be glued to the base of the pocket and once dried, the neck can be glued on. I'd recommend doing this as a 2-step process to avoid the shim being squeezed out under pressure if you tried to glue the neck and shim on at the same time.
You could of course use a single thin block of maple for the shim, but the veneer is probably easier to get hold of.
You can change the angle the heel directly, but it's harder to do accurately, and easier to get it wrong or introduce a sideways angle on the heel as well.
If a shim goes wrong, you can make another and another until it's right. If you get the neck heel angle wrong, you quickly run out of neck heel to adjust!