using System.Drawing;

Bitmap img = new Bitmap("*imagePath*");
for (int i = 0; i < img.Width; i++)
{
for (int j = 0; j < img.Height; j++)
{
Color pixel = img.GetPixel(i,j);

if (pixel == *somecondition*)
{
**Store pixel here in a array or list or whatever**
}
}
}