PNGOUTWin is described as 'You can use PNGOUTWin, an easy-to-use PNG optimizer, to create smaller image files and speed up your website, reach more potential customers, and decrease your bandwidth costs' and is an app in the Photos & Graphics category. There are more than 25 alternatives to PNGOUTWin for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and Wordpress. The best alternative is RIOT - Radical Image Optimization Tool, which is free. Other great apps like PNGOUTWin are ImageOptim (Free Personal, Open Source), XnConvert (Free Personal), TinyPNG (Freemium) and pngquant (Free, Open Source).
Saving images for web/email/other media with the best compression ratio and quality is a difficult task if you don’t have the right tools. Choosing the right format then choosing the right parameters are the key factors of smaller files.
ImageOptim is excellent for publishing images on the web (easily shrinks images “Saved for Web” in Photoshop). It's useful for making Mac and iPhone/iPad applications smaller (if you configure Xcode to allow better optimization).
XnConvert is an easy image converter for graphic files, photos and images available on Windows, MacOSX and Linux. It supports more than 400 file formats (jpeg, tiff, png, gif, camera raw, jpeg2000, WebP, OpenEXR, ...).
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.