You will need more than a standard graphics editor to produce a Tajima embroidery design (.dst file) from a PNG picture. Embroidery files are special vector based images with additional instructions for the stitching machine.
The only way to achieve such png to dst convesion would be to use some embroidery design program with a digitizing function, i.e. capable of processing raster data to vectors. Works best for simple geometric shapes. logos and poorly for photographs however.Open PNG file Open DST file
An embroidery designs manager
A set of applications used by professional graphic designers
An embroidery app for Illustrator
An embroidery digitizer