Dielectric materials that are low-loss in the visible spectrum provide a promising platform to realize the pragmatic features of metasurfaces. Here, all-dielectric, highly efficient, spin-encoded transmission-type metaholograms (in the visible domain) are demonstrated by utilizing hydrogenated amorphous silicon (a-Si:H). In comparison to previously reported visible metaholograms based on TiO2 and other dielectric materials, all-dielectric metasurfaces provide a cost-effective more straightforwardly fabricated (aspect ratio 4.7), CMOS compatible, and comparably efficient solution in the visible domain. A unique way of utilizing polarization as an extra degree of freedom in the design to implement transmission-type helicity-encoded metaholograms is also proposed. The produced images exhibit high fidelity under both right and left circularly polarized illuminations. The proposed cost-effective and CMOS-compatible material and methods open up an avenue for on-chip development of numerous new phenomena with high efficiency in the visible domain.