fft - How to analyze images with Fast Fourier Transform method?

I am learning about analyzing images with the method of FFT(Fast Fourier Transform). The image I am analyzing is attached below:

^{Portrait of woman posing on grass, by George Marks. Getty Images.}

And the result of the FFT analysis of this picture is presented below:

On the FFT image, the low frequency area is in the center of the image and the high frequency areas are at the corners of the image. Can someone tell me about the formation of the FFT image? For example, why is there a horizontal white line passing through the center? Also, why is the FFT image like a "sun" emitting beams?