Compress JPEGs without Artifacts
Compressing an image, especially a JPEG, to its smallest possible size often introduces ugly artifacts. JPEGmini Pro seeks to avoid that.
JPEGmini Pro reduces the file size of JPEG photos while preserving the originals' resolution and quality. It uses all of your processing cores and can process images of up to 50 megapixels. JPEGmini Pro uses parameters that have been tuned to reduce the file size without affecting perceptual quality and is based on a proprietary compressing algorithm that doesn't introduce quality loss. It's a bit like JPEG 2000 or WebP, but one of the major benefits of JPEGmini is that it doesn't require a whole new format that's supported by few Web browsers, if any.
JPEGmini analyzes the input image using a quality detector that imitates the human visual system. Based on this analysis the app applies the maximum amount of compression that won't cause visible artifacts at 100% magnification. Size reductions of 70-80% are achieved easily with JPEGs greater than 8 megapixels.
I tested JPEGmini Pro with three 40-megapixel Hasselblad files and a dozen 12-megapixel Sony Alpha files. This app is fast! The compression it achieved was equally impressive, and even a bit more than claimed with some of my photos. The visual characteristics of the JPEGmini Pro version were identical to the original when viewed at 100%. When magnified at 200%, I could see tiny differences in small details.
An added benefit of the desktop edition is the interface, which has a gauge showing you the reduction rate or how much disk space you've saved. In addition, in the preferences you can also set an image size reduction to one of three presets, or a customizable maximum width or height. Finally, you can choose to have the originals compressed or leave them alone. The Pro version also includes a plug-in for Adobe Lightroom.
Hot: No artifacts; excellent compression rates; fast
Not: Only compresses JPEGs