Cell growth is the basis for myriad biological processes ranging from development, regeneration and tumor growth. Yet how cell is maintained at the right size is still poorly understood. Accurate measurement of cell size is critical for providing answers to these open questions. I will describe the application and development of optical microscopy techniques including quantitative phase imaging and stimulated Raman scattering microscopy for investigation of the cell size regulation in skeletal development. Specifically, I will present Normalized Raman Imaging (NoRI) that measures the absolute concentrations of total protein, total lipid, and water at a high spatial resolution in tissue. NoRI achieves the absolute quantification by combining Stimulated Raman scattering (SRS) microscopy with a novel computational algorithm that removes the effect of light scattering in thick tissue samples. NoRI is a label-free technique that can measure live or fixed tissue sections, cultured cells and small model organisms without any use of staining. NoRI reveals that cell types and tissue types have characteristic protein and lipid density, which may change with developmental or disease processes.