Test.  Should print three identical images in plain format, twice each
P1
5 5
01010
10101
01010
10101
01010
P1
5 5
01010
10101
01010
10101
01010
P2
8 8
7
0 0 1 1 2 2 3 3
0 1 1 2 2 3 3 4
1 1 2 2 3 3 4 4
1 2 2 3 3 4 4 5
2 2 3 3 4 4 5 5
2 3 3 4 4 5 5 6
3 3 4 4 5 5 6 6
3 4 4 5 5 6 6 7
P2
8 8
7
0 0 1 1 2 2 3 3 
0 1 1 2 2 3 3 4 
1 1 2 2 3 3 4 4 
1 2 2 3 3 4 4 5 
2 2 3 3 4 4 5 5 
2 3 3 4 4 5 5 6 
3 3 4 4 5 5 6 6 
3 4 4 5 5 6 6 7 
P3
4 4
255
0 31 255  0 31 255  63 0 0  0 31 255
0 31 255  0 31 255  0 31 255  63 0 0
0 31 255  63 0 0  63 0 0  63 0 0
63 0 0  0 31 255  63 0 0  63 0 0
P3
4 4
255
0 31 255 0 31 255 63 0 0 0 31 255 
0 31 255 0 31 255 0 31 255 63 0 0 
0 31 255 63 0 0 63 0 0 63 0 0 
63 0 0 0 31 255 63 0 0 63 0 0