What's the point of your circuit?
It's a badly designed one ...
You basically have 2 strings of leds and in each string, the leds are connected in parallel. this means each string will only require the power supply to provide at least the forward voltage of an individual led. And, because the leds are connected in parallel, the current adds up, so each string because like a single led that needs 8 leds x 20mA = 160mA
So, both strings in total would require 320mA.
Now, if the leds are arranged this way, you would need to limit the current going into each string with a resistor.
You have the formula V = I x R so
Vin - (forward voltage led x number of leds ) = Current x Resistance where number of leds = 1 because you connected all 8 leds in parallel and current is 8 x 20mA again because parallel
so 12v - 10v = 0.160 x R => R = 2v / 0.160 = 12.5 ohm
And the power dissipated in the resistor would be P = IxIxR = 0.16 x 0.16x12.5 = 0.32w so you'd need a 0.5w rated resistor at minimum, ideally a 1w resistor for EACH string of leds.
In your picture both strings receive a limited amount of current ... 12v - 10v = I x 100 ... so I = 2 / 100 = 0.02A or 20mA , so each led would only consume 20 mA / 8 = 2.5mA
You can see here the proper way you should do it :
http://tinyurl.com/ybjmzqut - it's an online circuit simulator, you can right click on components to edit the values, and you can hover mouse over components to see voltage, current, power dissipated etc
If you don't want to click on shortened links or in case link dies, go to
http://www.falstad.com/circuit/ and use Import from text option in menu and paste this:
The exact current values and power in components in simulated circuit is just a tiny bit different than the math above, it's just the simulated leds consuming slightly different current (~22mA instead of 20mA each)
$ 1 0.000005 10.20027730826997 50 5 43
162 256 96 256 160 1 10 1 1 1 0.16
162 288 96 288 160 1 10 1 1 1 0.16
162 320 96 320 160 1 10 1 1 1 0.16
162 352 96 352 160 1 10 1 1 1 0.16
162 384 96 384 160 1 10 1 1 1 0.16
162 448 192 448 256 1 10 1 1 1 0.16
162 416 96 416 160 1 10 1 1 1 0.16
162 448 96 448 160 1 10 1 1 1 0.16
162 480 96 480 160 1 10 1 1 1 0.16
162 480 192 480 256 1 10 1 1 1 0.16
162 256 192 256 256 1 10 1 1 1 0.16
162 384 192 384 256 1 10 1 1 1 0.16
162 288 192 288 256 1 10 1 1 1 0.16
162 320 192 320 256 1 10 1 1 1 0.16
162 352 192 352 256 1 10 1 1 1 0.16
162 416 192 416 256 1 10 1 1 1 0.16
w 256 96 288 96 0
w 288 96 320 96 0
w 320 96 352 96 0
w 352 96 384 96 0
w 384 96 416 96 0
w 416 96 448 96 0
w 448 96 480 96 0
w 480 160 448 160 0
w 448 160 416 160 0
w 416 160 384 160 0
w 384 160 352 160 0
w 352 160 320 160 0
w 320 160 288 160 0
w 288 160 256 160 0
w 480 192 448 192 0
w 448 192 416 192 0
w 416 192 384 192 0
w 384 192 352 192 0
w 352 192 320 192 0
w 320 192 288 192 0
w 288 192 256 192 0
w 480 256 448 256 0
w 448 256 416 256 0
w 416 256 384 256 0
w 384 256 352 256 0
w 352 256 320 256 0
w 320 256 288 256 0
w 288 256 256 256 0
r 208 96 144 96 0 12.5
r 208 192 144 192 0 12.5
w 256 96 208 96 0
w 256 192 240 192 0
w 240 192 208 192 0
w 256 256 80 256 0
w 256 160 80 160 0
w 80 160 80 256 0
w 144 96 144 192 0
w 144 192 144 288 0
w 80 256 80 288 0
v 80 352 144 352 0 0 40 12 0 0 0.5
w 80 288 80 352 0
w 144 288 144 352 0
But anyway the problem with this kind of layout is that if one led dies shorted, each string is STILL limited to 160 mA so now instead of having 160 mA divided between 8 leds, so 20mA per led, you now have 160mA divided among 7 leds, which means each led in that string with a dead led will receive around 23mA .... If one of those 7 remaining leds is particularly sensitive to over current, it could die and then you have 6 leds which receive 160mA so each led now gets 160mA / 6 = 26.6mA ... you get the idea? You risk a cascade failure, where a tiny number of dead leds in string of parallel leds can kill the whole string of leds.