Sam2p
From MohidWiki
sam2p is a little utility that allows to convert between image file formats. Better than convert (generated eps filesizes are one-hundredfold smaller).
Example
Converting from jpg to eps:
> sam2p file.jpg EPS: file.eps
Batch convert from jpg to eps (windows):
> for %i in (*.jpg) do sam2p %i EPS: %~ni.eps