If you are getting inconsistent results or results that dont make any sense when trying to retrieve a black pixel eg:
(Red,Green,Blue)
0,0,0
0,0,0
0,0,2
0,0,4
0,0,6
0,0,7
0,0,0
0,0,10
0,0,8
0,0,9
0,0,0
0,0,12
0,0,13
0,0,0
switch from using imagecreate() to imagecreatetruecolor()
issue found when creating a graph where a pixel would increase in color based on the previous color and new data.