Web Development

If you ever need to transform to JPEG from Targa images (tga) - produced by some very popular games as screen shots - and you don't want to use the all mighty ImageMagick - which on my machine can process around 150 formats - you can try a simpler approach.

The simpler approach is cjpeg provided by the "Independent JPEG Group".

Follow up:

NAME
       cjpeg - compress an image file to a JPEG file

SYNOPSIS
       cjpeg [ options ] [ filename ]

DESCRIPTION
       cjpeg  compresses  the  named image file, or the standard input if no file is named, and produces a JPEG/JFIF file on the standard output.  The cur-
       rently supported input file formats are: PPM (PBMPLUS color format), PGM (PBMPLUS gray-scale format), BMP, Targa, and RLE (Utah Raster Toolkit  for-
       mat). (RLE is supported only if the URT library is available.)

I have used this on a project and the best results I had were with:

cjpeg -quality 70 -optimize -progressive -targa -restart 10 -max 15m -outfile OUT-FILE.JPG -verbose IN-FILE.TGA

The quality parameter can be changed as you wish... I ended up making it an extra configuration parameter thus I could tweak it to any value I wanted.

Of course, as you can see from the manual extract, it can compress other files as well.

It also has some nice companion programs:
djpeg - decompress a JPEG file to an image file

jpegtran - lossless transformation of JPEG files - transformations are done "without ever fully decoding the image"

rdjpgcom - display text comments from a JPEG file
wrjpgcom - insert text comments into a JPEG file

Have fun with it !