.X-PNG File

File extension x-png is associated with Portable Network Graphics file format, a bit-mapped graphics format similar to GIF. Approved as a standard by the WWW consortium to replace gif because gif uses a patented data compression algorithm called LZW. In contrast, PNG is completely patent- and license-free. Only the previous versions of Netscape Navigator and Microsoft Internet Explorer supported PNG file format. Today's all commonly used browsers can display PNG file format correctly.

png is a bitmap compression method for image files. PNG supports 16.7 million colors, it is lossless and also supports index color, grayscale, true color, transparency, and is streamable. It is thus the best compression method (better than GIF or JPEG) for use on the web.

MIME types:
image/png

How to open:

Any graphic editor should be able to open .x-png files.

How to convert:

Apparently, .x-png files can be converted pretty much like any other PNG file.