You can download best freeware soft here!

Optimize and convert your graphic files/images in smaller PNG files (up to 5-30%) lossless! Full compatible with source PNG format. Convert from PNG, GIF, BMP, PNM, TIFF to smallest PNG! It uses 6 programs and selects the best result: OptiPNG, TruePNG, ECT (Efficient Compression Tool), AdvanceCOMP, PNGWolfZopfli, DeflOpt. You can enable or disable each of them. Batch processing of files (drag-n-drop). Reduce the size of your PNG files in one click without quality loss! Program optimizes your file to new one with «_optimized» name ending (source file will remain intact). Program will be especially useful for webmasters to optimize images on sites to increase places in search results.