Following these three WORD values is a series of structures describing the images. The only values in this substructure that are truly necessary are the image size and image offset values. The rest of the values are merely a hint and should not be relied upon because they may not always be populated correctly. In most cases you should simply ignore them since you can learn everything you need to know about the images by inspecting the DIB or PNG image bits themselves. The image size indicates how many bytes are occupied by the image. The image offset indicates the offset from the beginning of the file to the start image bits.