How to convert .tga files to .png?
I would recommend the convert command from ImageMagick. It can convert almost any graphics format into any other.
$ convert image1.tga image1.png
For those of you who are looking to convert more than one file you can use ImageMagick's built-in command "mogrify". First cd to the directory with the files you want to convert then run the following command:
$ mogrify -path [output-folder] -format [desired-output-format] *.[desired-input-format]
For example:
$ mogrify -path output-folder/ -format png *.tga