Image Brightness on 2D Fourier Transformation
If I understand correctly only phase would change not frequency. Is that correct?


Assuming "increasing brightness by 10%" just means multiplying each pixel's value with 1.1:

No, the phase won't change either. Since the Fourier Transform is a linear operation, you just multiply every point in the spectrum by the same factor. That doesn't affect phase, since 1.1 is a real number.