A highly simplified architecture for stimulated-Raman-scattering microscopy is demonstrated, where multiple tunable narrowband picosecond pulses are generated by spectral compression of femtosecond pulses emitted by a single compact Er-fiber oscillator. The system provides high sensitivity $\left(2\times {10}^{-7}\right)$ and spectral resolution $\left(\text{sub-}15{\text{cm}}^{-1}\right)$ , and it offers an unprecedented flexibility for multicolor imaging.