Those users who are usually working all the time with PNG graphic files will appreciate this tool called Png Optimizer.
It is a tool, totally free, that will allow you to optimize graphics in PNG eliminating all the expendable and unnecessary information that they do not need; in this way, said PNG will weigh much less (ideal when there are dozens of PNGs to process).
In addition, Png Optimizer allows you to convert each PNG to other formats, such as BMP, GIF or TGA, as well as make your own screenshots in PNG format.
It is interesting for programmers the fact that on the website of the author of Png Optimizer they can find the source code, to know how the program is made.
You can free download Png Optimizer 32, 64 bit and safe install the latest trial or new full version for Windows 10 from the official site.