We present a software package for computing piecewise rational reparameterizations of parametric plane curves, which have improved uniformities of angular speed. The package ImUp is implemented in Maple on the basis of some recently developed algorithms of reparameterization using piecewise Möbius transformations. We discuss some implementation issues and illustrate the capability and performance of the public functions of ImUp with examples and experiments. It is shown that the quality of plots of plane curves may be effectively improved by means of reparameterization using ImUp.