The dynamical study of nearby dwarf spheroidal galaxies has played a fundamental role in challenging the cold dark matter model. These studies, based on the analysis of resolved stellar populations, are limited by the fact that we can only probe a small population of the nearest nearby galaxies. In the coming years, ultra-deep surveys will increase by several orders of magnitude the number of low-mass galaxies with similar properties to nearby spheroidal galaxies. However, our knowledge of these objects will be limited to the study of their integral properties. The present work bridges these two types of analysis. To do this, we have carried out ultra-deep imaging of these nearby galaxies using telescopes that are modest in diameter but have a large field of view. This is essential to overcome the problem of oversubtraction of the outskirts of galaxies that plagues current deep imaging of nearby galaxies with large telescopes. In this way, we will see the nearby galaxies with a resolution similar to what they would be if they were outside the local group. In particular, in addition to these deep images, we will present an analysis of the surface stellar mass density profiles, which we will compare with dynamical analyses based on resolved populations. We will show to what extent the dynamical core sizes can be recovered from the image-based information alone. The size distribution of the cores, based on the study of hundreds of galaxies in the near future, will be one of the strongest constraints on alternative dark matter models.