PNGGauntlet can compress PNG images to make them more efficient, so reducing file size while maintaining the same image quality. This can be particularly good news on websites, where it makes pages faster to load and reduces your bandwidth requirements, but this kind of shrinkage has advantages anywhere that PNG files are used.
The program works by combining three open-source image optimisation tools - PNGOUT, OptiPNG and DeflOpt - to deliver the best possible compression.
But while these core tools are fairly complex, you don't have to understand any of the low-level technicalities to use PNGGauntlet. Just drag and drop your target images onto the program, choose an Output folder, click "Optimize!" and watch as your images are tweaked.
Does it work? We tested the program with six large PNG-format logos. These were found online, so we'd expect them to be reasonably compressed already, but PNGGauntlet still achieved impressive results. One file was reduced from 71.63KB to 39.44KB in size (a 44% cut); others were cut by 24%, 20% and 7%, and even the best compressed two were still reduced in size by a few bytes.
That's not bad at all. If you need more control, though, clicking Tools > Options does give you access to the various PNGOUT, OptiPNG and DeflOpt settings (although you will need a good understanding of low-level PNG structures to get the most from them).