Most simple nonlinear thresholding rules for wavelet- based denoising assume that the wavelet coefficients are independent However  wavelet coefficients of natural images have significant dependencies This paper attempts to give a recipe for selecting one of the popular image-denoising algorithms based on VisuShrink  SureShrink  OracleShrink  BayesShrink and BiShrink and also this paper compares different Bivariate models used for image denoising applications