Leanify is described as 'lightweight lossless file minifier/optimizer. It removes unnecessary data (debug information, comments, metadata, etc.) and recompress the file to reduce file size. It will not reduce image quality at all. Features' and is an app in the File Management category. There are more than 10 alternatives to Leanify for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and Wordpress. The best alternative is FileOptimizer, which is both free and Open Source. Other great apps like Leanify are TinyPNG (Freemium), PNGGauntlet (Free), Pingo Web Image Optimizer (Free) and Oxipng (Free, Open Source).
TinyPNG uses smart lossy compression techniques to reduce the file size of your PNG files. By selectively decreasing the number of colours in the image, fewer bytes are required to store the data. The effect is nearly invisible but it makes a very large difference in file size!
Experimental, fast Web PNG/JPG optimizer which offer lossless, visually lossless or lossy compression. it performs image reductions over iterations thanks to recursive multi-processing and multithreading systems.
OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections.
PngOptimizer compresses graphics files and removes extra, unnecessary data without affecting quality. It will update PNG files or converting BMP, GIF or TGA files to the PNG format using simple drag-and-drop.
AdvanceCOMP is a collection of recompression utilities for your .ZIP archives, .PNG snapshots, .MNG video clips and .GZ files. It's mainly intended for recompressing your rom, snapshot and clip collection of emulated games.
TruePNG is one of the most advanced PNG optimizers available. It does the most exhaustive checks for reductions, that lets it to optimize further, even if it uses a less efficient compression algorithm than others tools.