Here is Converseen 0.9.9.6, the open-source and cross platform batch image processor that allows you to convert, resize, rotate and flip an infinite number of images with a mouse click.
What’s New in Converseen 0.9.9.6
In this new version of the program I added an improved dialog for adjusting the JPEG quality settings and the PNG compression level using the features offered by ImageMagick.
How the Quality/Compression Features Work
For the JPEG and MPEG image formats, quality is 1 (lowest image quality and highest compression) to 100 (best quality but least effective compression).
For the JPEG-2000 image format, quality is mapped using a non-linear equation to the compression ratio required by the Jasper library. This non-linear equation is intended to loosely approximate the quality provided by the JPEG v1 format. The default quality value 100, a request for non-lossy compression. A quality of 75 results in a request for 16:1 compression.
For the MNG and PNG image formats, the quality value sets the zlib compression from 1 to 9 (1 is lowest and 9 is highest).
For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.
PNG uses a ‘lossless’ compression method, so increasing the compression does NOT reduce your image quality.