With the increased design complexities brought in by applying different Reticle Enhancement Technologies (RETs) in nanometer-scale IC manufacturing process, post-RET sign-off verification is quickly becoming necessary. By introducing innovative algorithms for lithographic modeling, silicon imaging and yield problem locating,this paper describes a new methodology of IC manufacturability verification based on Dense Silicon Imaging (DSI). Necessity of imaging based verification is analyzed.Existing post-RET verification methods are reviewed and compared to the new methodology. Due to the greatly improved computational efficiency produced by algorithms such as the ～16*log2N/Iog2M times faster Specialized FFT, DSI based manufacturability checks on full IC scale, which were impractical for applications before,are now realized. Real verification example has been demonstrated and studied as well.