ptx to png conversion is most likely searched by users that are looking for a way to export digital RAW photographs from Pentax PTX format, to standard PNG format. Typically Pentax files use PEF extension and PTX is either rare or used for older format.
In any case, you will need to use digital photo editors that support Pentax formats, either directly or via plugin. You can possibly find more options under pef to png conversion entry.
Updated: November 3, 2023