The TGA format was developed by Truevision as a way of storing color images, specifically 24 and 32-bit color images. The format is sometimes known incorrectly as "Targa" which refers to the graphics hardware for which the format was originally designed.
The TGA format is lossless (no image data is discarded during saving) and supports high-color images.
The TGA format can be RLE (Run Length Encoding) compressed which results in significantly smaller file sizes, but will give slower performance when handling the image.