These are the results of a image transformation test as described in this artice by Marius Lessiak

Benchmark results for image downscaling

Benchmarks taken with junit-benchmarks using 200 runs

1 run consits of downscaling 3 images 2 times, resulting in 6 downscaling operations

Image quality when downscaled from width 472 pixels to 1/2 and 1/4

From left to right: original, ImageScalr, java-image-scaling, ImageMagick, GraphicsMagick