Hi. Thanks for the quick reply.

I've played with arrays before... but safearray? used with CopyMemory()? Guess I'll have to search the forum because I didn't know about CopyMemory. If you have any examples on this, feel free to post, but I guess I'll find on the forums.

I'd like to check the logic with you tho. I guess I would have to:

1- Copy picOriginal to array1
2- Draw blue line on picBlueLine
3- Copy picBlueLine to array2
4- Search array2 for blue pixels and compare X,Y coords to array1
...and loop steps 2,3,4 (because I am comparing several lines)

Do I have a fairly good logic on this? If so, do you think that step3 (copying picBlueLine to array2), after every new blue line, will be quicker than just comparing with .Point? If so - I'm glad, I'll try out. It'll have to copy a picturebox (300 pixels / 70 pixels) to array2 about 500 times, only to pinpoint the location of a newly added blue line.

Hey thanks a lot for your input, 'appreciate it.