| 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 colors down to 256 or 16 colors to help reduce the file size of the PNG.
The STL, or Standard Triangle Language, file format has been around since the '80s and is supported by most modern 3D modeling applications. In particular, the STL format has become something of a standard format within the area of 3D printing, despite the rise of more modern formats such as 3MF.
STL files come in two flavors: binary or text format. The text format is human-readable, making it easy to perform manual edits, but can lead to very large file sizes. As you can imagine, the binary format is much more compact and represents the majority of the STL files you are likely to encounter.
The format itself is very simple; the 3D model is represented by a sequential list of triangles, with each triangle defined with 3 points consisting of their X, Y, and Z positions, along with an additional vector that contains the face normal (the direction the face is pointing). There is an additional attribute block for each triangle; however, this is largely unused and thus unsupported.
