Can gliders and single-engine planes have vortices?
The vortices that you are referring to (I think) are wing-tip vortices, a product of the wing generating lift.  Since glider wings do generate lift (due to the airflow over the wing) and are propelled (without engine created propulsion) wing-tip vortices are created. Single engine airplanes also create wing-tip vortices since lift is being generated (aided by propulsion)
The jet in your photo is showing &quot;vapor trails&quot; or &quot;contrails&quot; from condensation (from the engines' exhaust) and are not wing-tip vortices.
I'm pretty certain there are a number of engineers on ASE that could provide a more technical answer, but the bottom line is the engines of an airplane do not create vortices (in the context of wing-tip vortices that I believe you are thinking of).