Picturing the density inhomogeneity of matter at recombination The CMB was formed at the time of recombination which suggests that the analysis of the temperature anisotropies of the CMB helps to infer the profile of density fluctuations at the time of recombination. If that is true, is it possible to reconstruct a picture (analogous to this) of the density distribution of matter (including ordinary and dark stuff) at that moment? 
 A: The answer is yes. At the time of the last scattering, On the large scales ($\theta>\theta_H$) the blueshifted and redshifted parts on the CMBR can be explained by the dark matter distribution/fluctuations. This effect is also called "Non-integrated Sachs–Wolfe effect"
Dark matter was dominant in these fluctuations because at the time of the last scattering when we calculate the energy densities we see that, 
$\epsilon_{dm}>\epsilon_{rad}>\epsilon_{bary}$
Essentially photons can pass less denser areas without losing much energy so these areas are blueshifted, meanwhile, when photons coming from more denser areas they become redshifted. 
We can also use the idea of potential wells and potential maxima's to describe the situation. In climbing out of the potential well, photon loses energy and consequently is redshifted. Conversely, a photon which happens to be at a potential maximum when the universe became transparent gains energy as it falls down the “potential hill”, and thus is blueshifted.
So when we look at the CMBR the blueshifted areas represent less dense areas meanwhile, the redshifted ones more dense areas.
In the CMBR we can also see the matter effects but in small scale fluctuations.  This effect can be explained by the acoustic oscillations of the photon-baryon fluid, caused by the dark matter potential wells. After the photon decoupling era when the fluid makes an oscillatory motion (compresses and expands), it emits photons which are redshifted and blueshifted due to the doppler effect caused by this copression and expansion of the fluid. 
We can also see why these fluctuations happen on the small scales since dark matter energy density is greater then the others it creates the largest effect on the CMBR.
