ico The .ICO filename extension refers to the ICON image file format originally developed by Microsoft. The extension is used to represent computer icon images of varying sizes designed for the operating system Microsoft Windows. Its use today has extended to developing icons for programs designed using the Microsoft developer's suite Visual Studio and other applications. Similar to other device independent bitmap file formats, the ICON file format is also in the raster graphics class of image formats where each individual pixel is part of an orthogonal dot matrix data structure with support for a limited palette of color information. As a resource file, the .ico file format has its strength in contextual use. This allows for multiple icon images of different color depth or size to be stored within the resource file and used when appropriate.
tga The .tga filename extension refers to the Truevision raster graphics file format. It is a graphics format that was developed by Truevision incorporated in 1984, a company which was later acquired by Avid Technology. The company was known for developing computer daughter boards designed for digital video authoring and editing. These boards used the Truevision TGA format natively for digital video editing and were supported by both PC and Macintosh at the time.