To provide an image forming apparatus, a system and a method for printing images, and programs, which can perform black and white outputs in one K color material for image data, such as that that a white board is color photographed, to save CMY color materials, and acquire clear and more appropriate printed images with less bleeding or scattering.

The image forming apparatus has an image data color determination means 42 for determining whether an image file received from an image supply apparatus is photographed in color or black and white, and a printing mode determination means 43 for determining whether image data in the image file, which is determined to have been color photographed by the image data color determination means 42, is printed in color or black and white. In addition, the image forming apparatus also has an image conversion means 45 for converting the image data in the image file photographed in color, which is determined to be printed in black and white by the printing mode determination means 43, into a black and white image.