We present an efficient virtual-optical multiplexing method for compressing information contained in gray level images. The efficiency is measured using three parameters: quality factors of recovered images, memory saving percentage achieved, and number of multiplexed images in the package. Theta modulation techniques are applied, to process an N number of gray level images, by using a virtual-optical 2f architecture, from which we obtain a complex package M, to be stored as two images, amplitude and phase, in commercial formats. We apply pixel optimization and Fourier plane filtering to amplitude and phase images, respectively, storing only a percentage of the Fourier plane with a pixel dynamic range optimization. The stored package spends much less memory than individual images. The recovered images after the demultiplexing process are compared with the original ones by using correlation coefficient, obtaining high quality factors for decompressed images. We perform simulations, showing the efficiency of the proposed process, and our results are compared to the same factors reported in recent publications, making our improvements evident.