oxipng — oxipng.exe -o 2 --libdeflater --alpha --strip all

file insize instate stats outsize outstate savings
chart1.png 321684 bytes /c2 /f4 /n32
Kernel  Time =     0.000 =    0%
User    Time =     0.734 =  185%
Process Time =     0.734 =  185%    Virtual  Memory =     25 MB
Global  Time =     0.395 =  100%    Physical Memory =     15 MB
250626 bytes /c2 /f0 /n51 71058 bytes
chart2.png 574423 bytes /c2 /f4 /n23
Kernel  Time =     0.015 =    2%
User    Time =     0.968 =  176%
Process Time =     0.984 =  179%    Virtual  Memory =     27 MB
Global  Time =     0.549 =  100%    Physical Memory =     22 MB
505330 bytes /c2 /f5 /n63 69093 bytes
chart3.png 517620 bytes /c2 /f4 /n28
Kernel  Time =     0.000 =    0%
User    Time =     0.781 =  167%
Process Time =     0.781 =  167%    Virtual  Memory =     26 MB
Global  Time =     0.465 =  100%    Physical Memory =     16 MB
440749 bytes /c2 /f0 /n77 76871 bytes
chart4.png 136899 bytes /c2 /f4 /n10
Kernel  Time =     0.031 =    9%
User    Time =     0.578 =  176%
Process Time =     0.609 =  185%    Virtual  Memory =     23 MB
Global  Time =     0.328 =  100%    Physical Memory =     17 MB
124663 bytes /c2 /f5 /n11 12236 bytes
chart5.png 758590 bytes /c2 /f4 /n22
Kernel  Time =     0.000 =    0%
User    Time =     0.937 =  175%
Process Time =     0.937 =  175%    Virtual  Memory =     28 MB
Global  Time =     0.535 =  100%    Physical Memory =     16 MB
555861 bytes /c2 /f0 /n108 202729 bytes
chart6.png 309145 bytes /c2 /f4 /n25
Kernel  Time =     0.031 =    9%
User    Time =     0.562 =  167%
Process Time =     0.593 =  176%    Virtual  Memory =     24 MB
Global  Time =     0.336 =  100%    Physical Memory =     22 MB
261863 bytes /c2 /f0 /n19 47282 bytes
chart7.png 590400 bytes /c2 /f4 /n16
Kernel  Time =     0.046 =    7%
User    Time =     1.062 =  175%
Process Time =     1.109 =  183%    Virtual  Memory =     27 MB
Global  Time =     0.604 =  100%    Physical Memory =     20 MB
467813 bytes /c2 /f0 /n29 122587 bytes
chart8.png 155980 bytes /c2 /f4 /n8
Kernel  Time =     0.000 =    0%
User    Time =     0.718 =  179%
Process Time =     0.718 =  179%    Virtual  Memory =     24 MB
Global  Time =     0.399 =  100%    Physical Memory =     18 MB
122232 bytes /c2 /f0 /n19 33748 bytes
total savings 635604 bytes
total time 3,61 seconds