What is the definition of a PNG 8 file type?

A PNG 8 file type is defined as a file format that supports only 256 colors, making it a suitable substitute for GIF. This limitation allows PNG 8 files to effectively compress images with limited color palettes while still maintaining decent quality for simple graphics. This makes them ideal for storing images such as logos, icons, or any artwork that doesn't require extensive color variation.

The context of its use is particularly relevant in situations where file size is a consideration, as PNG 8 files are generally smaller than their high-color counterparts. The format also retains the ability to include transparency, which is a significant advantage over GIF in some applications, particularly in web design.

Other options describe file types or characteristics that do not apply to PNG 8. For instance, stating unlimited colors is incorrect as it would refer to PNG 24 format. High-resolution formats ideal for detailed images would relate more to other image file types like TIFF or RAW, which support much larger color depths. Lastly, a format primarily used for text documents is inaccurate, as PNG is designed for images rather than textual data, which would be more appropriate for formats like DOC or PDF.