The author of Mango posted a benchmark on Reddit: https://www.reddit.com/r/programming/comments/mld1ob/the_fas...

                  load         save             
  ----------------------------------------------
  // image: 1165 x 859 (1943 KB) 24bpp
  libpng:       19.2 ms     494.7 ms 
  wuffs:        14.9 ms       0.0 ms 
  mango:        10.0 ms      84.7 ms 

  // image: 312 x 442 (43 KB) 32bpp
  libpng:        2.9 ms      18.3 ms 
  wuffs:         0.4 ms       0.0 ms 
  mango:         0.1 ms       7.3 ms 

  // image: 160 x 120 (13 KB) 8bpp
  libpng:        0.7 ms       9.5 ms 
  wuffs:         0.1 ms       0.0 ms 
  mango:         0.1 ms       3.2 ms 

  // image: 90 x 112 (23 KB) 24bpp
  libpng:        0.9 ms       3.9 ms 
  wuffs:         0.5 ms       0.0 ms 
  mango:         0.2 ms       1.3 ms