Two possible dst to jpg conversion exist.
Export Tajima embroidery design as JPEG
Export of Tajima embroidery format (.dst) to a JPEG format (.jpg), most likely for preview purposes. This can be typically done in an embroidery software with previewing function which allows users to save the designs as images or PDFs. In this case the resulting file will not be useable in stitching machines anymore.
Save Micrografx Designer template as JPG image
Another possible conversion would be the import of old Micrografx Designers templates (also .dst) and save them as JPEGs. Supposedly, some versions of CorelDraw could do that, but no further information about this could be found.Open DST file Open JPG file
A set of applications used by professional graphic designers