the tga file is a kind of image file:
http: // en.wikipedia.org/wiki/Truevision_TGA"
"Truevision's (now AVID) TGA File Format, often referred to as TARGA File Format, is a raster graphics file format. It was the native format of Truevision Inc.'s TARGA and VISTA boards, which were the first graphic cards for IBM-compatible PCs to support Highcolor/truecolor display. This family of graphic cards was intended for professional computer image synthesis and video editing with PCs; for this reason, usual resolutions of TGA image files match those of the NTSC and PAL video formats."
it is another graphics format like .gif or .jpg, but old and rarely used