private void createFlash(){
                AssetManager assetManager = getApplication().getAssetManager();
                flash = new ParticleEmitter("Flash", ParticleMesh.Type.Point, 24 );
                flash.setSelectRandomImage(true);
                flash.setStartColor(new ColorRGBA(1f, 0.8f, 0.36f, 1f ));
                flash.setEndColor(new ColorRGBA(1f, 0.8f, 0.36f, 0f));
                flash.setStartSize(.1f);
                flash.setEndSize(3.0f);
                flash.setShape(new EmitterSphereShape(Vector3f.ZERO, .05f));
                flash.setParticlesPerSec(0);
                flash.setGravity(0, 0, 0);
                flash.setLowLife(.2f);
                flash.setHighLife(.2f);
                flash.getParticleInfluencer()
                        .setInitialVelocity(new Vector3f(0, 5f, 0));
                flash.getParticleInfluencer().setVelocityVariation(1);
                flash.setImagesX(2);
                flash.setImagesY(2);
                Material mat = new Material(assetManager, "Common/MatDefs/Misc/Particle.j3md");
                mat.setTexture("Texture", assetManager.loadTexture("Effects/Explosion/flash.png"));
                mat.setBoolean("PointSprite", true);
                flash.setMaterial(mat);
                explosionEffect.attachChild(flash);
            }
This test's particle effects (using an explosion)
jme3-screenshot-tests/src/test/java/org/jmonkeyengine/screenshottests/effects/TestExplosionEffect.java