Mini Mandelbrots, are they exact copies?

I found a distorted "mini mondelbrot"

They are not exact copies, as some of the comments have pointed out. They each have a point where the n-fold iteration of $z \to z^2+c$ produces zero. The reason they are approximate copies is that the iteration is differentiable, so points near the n-fold zero behave "like" points near 0 in the main bulb. There are a number of measures of geometric similarity you could use, for example comparing the ratios of radii of the satellites to the main cardioid, their angular positions, etc. You might be able to express these in terms of the derivatives of the iteration at the preimage of 0.