| Extension | PNG |
| Full Name | Portable Network Graphics |
| Type | Image |
| Mime Type | image/png |
| Format | Binary |
| Opens With | Paint.Net, Photoshop |
PNG files are a widely used graphics file format used in areas where high-quality images (often with transparency) are required while also retaining a small file size. They are one of the most common formats of file used for web and print mediums and are particularly useful for logos, icons, and other images where multi-level transparency is desired.
The format itself was created in the 1990's with the main aim of storing computer graphics in a high-quality format while minimizing the required storage space. The longer-term aim was to displace the GIF file format and make PNG the number one format for non-lossy, high-quality image formats on the then-burgeoning world wide web.
One of the selling points of the PNG format is its support for multiple levels of transparency, making it superior to the GIF format, which can only handle a single level of transparency. Also, like GIFs, the PNG format supports palletizing image colours down to 256 or 16 colours to help reduce the file size of the PNG.
| Extension | TXT |
| Full Name | Data URI Scheme |
| Type | Document |
| Mime Type | text/plain |
| Format | Text |
A data uri is a form of specially encoded ASCII text content that is usually treated as plain text and may thus use the TXT file extension. A data URI is used as a means of storing binary data in a text format with the use of Base64 encoding.
A blob of binary data is Base64 encoded, a process of converting individual bytes of data into an ASCII representation using several characters per byte. This process, once completed, will result in a text file roughly 25% larger than the original binary data file.
The main reason for encoding binary data in such a way is to enable binary files, such as images, to be embedded into HTML and CSS files used by websites. This embedding of the images as text reduces the number of HTTP requests a website needs to make, thus decreasing the load time of websites.
