The compression of PNG files is lossless, and the process itself consists of two stages. The first is pre-compression, and the second is actual compression, eliminating duplicate byte sequences.

To compress, perform the following steps:

• Load the image to be compressed;
• Compression can be performed in different quality parameters (from 250 to 0), which can be selected in the settings menu item. The future size of the image depends on the quality parameter. In the settings field, you can immediately see what the output file will be, which allows you to set the desired parameters without wasting time
• The compressed image is downloaded to the PC.

The free online tool Png-compress can optimize png images without the risk of losing image quality.

Favicon is an online service for a webmaster to convert png to ico.