Well I will try to answer your question.
Well basically, as I understand it, there are three requirements for a photo to be acceptable. First, it has to pass through the photo validator system. Where it is checked for its size, whether it is 24 bit, whether it is a JPEG file and whether it is a 600 pixels X 600 pixels. If the photo meets these basic requirements then it passes the photo validator step. Next comes the compositional requirements. By which I mean that head of the photo should be straight not tilted to one side. The head size, defined as the area between the top of head and the chin should be between 55% and 69 % of the total size of the photo. Also the eye level, defined as the area between the bottom of the photo and the level of corner of the eye should be at the max 69% of the total area of the photo. Thirdly, the photo must be recent, which is defined as being taken at the max six months before the date of applying.
Although I don’t work and have never worked for KCC, I infer from the other posts in this discussion forum that once the photo passes the photo validator step then it is most probably accepted. This is mainly because the compositional parts like the head size and the eye level has to be determined manually. There is no software present currently that will give the head size or the eye level of the photo. It has to be done by hand by a person most probably by the help of a ruler and a calculator.
Hope that helps.