How to change the arrow size of the graph in Graphviz

Question

When I use the penwidth to change the edge width in Graphviz, the arrow size has been enlarged which has a strange behavior. How could I change the thickness of the edge with a proper arrow size ?

strict digraph  {
rankdir=LR;
0 [image="./state01.png", label="", shape=none];
1 [image="./state02.png", label="", shape=none];
2 [image="./state03.png", label="", shape=none];
3 [image="./state04.png", label="", shape=none];
4 [image="./state05.png", label="", shape=none];
5 [image="./state06.png", label="", shape=none];
6 [image="./state07.png", label="", shape=none];
7 [image="./state08.png", label="", shape=none];
8 [image="./state09.png", label="", shape=none];
9 [image="./state10.png", label="", shape=none];
10 [image="./state11.png", label="", shape=none];
11 [image="./state12.png", label="", shape=none];
0 -> 10  [arrowsize=2, color=red, fontsize=100, label="1.41e-06", penwidth="2.5", style=bold];
1 -> 5  [arrowsize=2, color=red, fontsize=100, label="2.80e-05", penwidth="3.874038546143974", style=bold];
2 -> 8  [arrowsize=2, color=red, fontsize=100, label="1.51e-07", penwidth="2.5", style=bold];
2 -> 11  [arrowsize=2, color=red, fontsize=100, label="1.83e-07", penwidth="2.5", style=bold];
3 -> 11  [arrowsize=2, color=red, fontsize=100, label="3.00e-06", penwidth="2.5", style=bold];
4 -> 7  [arrowsize=2, color=red, fontsize=100, label="4.58e-04", penwidth="63.38415155484499", style=bold];
5 -> 4  [arrowsize=2, color=red, fontsize=100, label="1.61e-04", penwidth="22.296681458902984", style=bold];
5 -> 7  [arrowsize=2, color=red, fontsize=100, label="1.30e-05", penwidth="2.5", style=bold];
6 -> 1  [arrowsize=2, color=red, fontsize=100, label="2.38e-05", penwidth="3.292282525626318", style=bold];
6 -> 5  [arrowsize=2, color=red, fontsize=100, label="7.38e-05", penwidth="10.21068283906899", style=bold];
6 -> 11  [arrowsize=2, color=red, fontsize=100, label="3.56e-05", penwidth="4.9292236040484125", style=bold];
8 -> 0  [arrowsize=2, color=red, fontsize=100, label="1.41e-06", penwidth="2.5", style=bold];
8 -> 10  [arrowsize=2, color=red, fontsize=100, label="4.98e-05", penwidth="6.895987834174217", style=bold];
9 -> 1  [arrowsize=2, color=red, fontsize=100, label="6.55e-07", penwidth="2.5", style=bold];
9 -> 2  [arrowsize=2, color=red, fontsize=100, label="3.33e-07", penwidth="2.5", style=bold];
9 -> 6  [arrowsize=2, color=red, fontsize=100, label="1.33e-04", penwidth="18.42707006915772", style=bold];
9 -> 8  [arrowsize=2, color=red, fontsize=100, label="4.65e-05", penwidth="6.4296145772978734", style=bold];
9 -> 10  [arrowsize=2, color=red, fontsize=100, label="4.09e-05", penwidth="5.661779639397044", style=bold];
9 -> 11  [arrowsize=2, color=red, fontsize=100, label="2.58e-04", penwidth="35.681635435845244", style=bold];
10 -> 3  [arrowsize=2, color=red, fontsize=100, label="3.00e-06", penwidth="2.5", style=bold];
10 -> 6  [arrowsize=2, color=red, fontsize=100, label="3.80e-08", penwidth="2.5", style=bold];
10 -> 11  [arrowsize=2, color=red, fontsize=100, label="8.91e-05", penwidth="12.331844148599716", style=bold];
11 -> 1  [arrowsize=2, color=red, fontsize=100, label="3.54e-06", penwidth="2.5", style=bold];
11 -> 4  [arrowsize=2, color=red, fontsize=100, label="2.97e-04", penwidth="41.082766242268384", style=bold];
11 -> 5  [arrowsize=2, color=red, fontsize=100, label="7.23e-05", penwidth="10.00537346107893", style=bold];
11 -> 7  [arrowsize=2, color=red, fontsize=100, label="8.43e-06", penwidth="2.5", style=bold];
11 -> 8  [arrowsize=2, color=red, fontsize=100, label="4.63e-06", penwidth="2.5", style=bold];
}