TGA is a raster graphic format. It was originally created by Truevision Inc. for graphics cards has its own production in 1984, but later became popular on a variety of platforms, especially in the field of video editing, animation. Format supports color depths 1-32 bits per pixel. There is support for alpha channels, compression RLE.
PNG is a raster graphic data storage format that uses lossless compression algorithm to Deflate. PNG was created as a free format to replace GIF. PNG supports three main types of raster images: grayscale image, a color indexed image and the color image. PNG format stores graphical information in a compressed form.