Image compression algorithms comparison

1. What is the best image compression algorithm?
2. What is the fastest compression algorithm?
3. Which algorithm has highest compression ratio?
4. Is there a perfect compression algorithm?

What is the best image compression algorithm?

The DCT is sometimes referred to as "DCT-II" in the context of a family of discrete cosine transforms (see discrete cosine transform). It is generally the most efficient form of image compression. DCT is used in JPEG, the most popular lossy format, and the more recent HEIF.

What is the fastest compression algorithm?

LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core, scalable with multi-cores CPU. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.

Which algorithm has highest compression ratio?

The fastest algorithm, lz4, results in lower compression ratios; xz, which has the highest compression ratio, suffers from a slow compression speed. However, Zstandard, at the default setting, shows substantial improvements in both compression speed and decompression speed, while compressing at the same ratio as zlib.

Is there a perfect compression algorithm?

No. It can be proven that there is not even an algorithm to determine how well a perfect compressor will do. See Kolmogorov Complexity. Huffman coding (or arithmetic coding) by itself does not get close to the best compression.