Out of the several conversion tools (ImageMagick, GIMP), the most effective, IMO, is
sam2p. It produces the smallest EPS possible.
sam2p is available in Debian repositories.
sam2p is a command line tool. To convert a PNG file
image.png to EPS file
$ sam2p image.png EPS: image.eps
I have tried converting some Google Earth screenshots (they are fairly complicated images with a lot of details). These are the sizes of original PNG and of converted EPS images (with ImageMagick's
convert and with
$ ls -rSsk1 google-earth-screenshot* 1756 google-earth-screenshot.png 3016 google-earth-screenshot-(sam2p).eps 4304 google-earth-screenshot-(convert).epsCertainly, sam2p-produced EPS is larger than PNG, but it is much smaller than convert-produced EPS. On some images the difference may be even bigger.
BTW, EPS produced by
sam2p is EPSF-3.0, and should be compatible with the most of vector graphics software. It seems like often using
sam2p may be a better option than using built-in import raster tool. At least when the size of the file matters.
Another tool for effective conversion from raster to EPS is
bmeps, but I have not tried it.
P.S. I wrote this post also in Russian: Эффективная конвертация растра в EPS или PDF.