Where can we find noises like Gaussian, Rayleigh, Gamma, exponential noises in real world images?
Gaussian Noise: Standard model of amplifier noise.

Gamma Noise: Frequent in Radar/LiDAR.

Rayleigh Noise: One example where the Rayleigh distribution naturally arises is when wind velocity is analyzed into its orthogonal 2-dimensional vector components. 

Exponential Noise: Channel Based Communication(see AEN).