I'm interested in trying to figure out how the animator created this effect that looks similar to a slide projector effect at :29 seconds in this video below
That's nothing more than animating position with possibly a feathered edge mask and motion blur enabled. There are spots where an animated gradient may have been added using the multiply or overlay blend mode. No plug-in's involved, just manual animation. Pretty basic stuff.
Ok let me see if I get this right, they have multiple copies of the same picture and in some cases animating it upwards on the Y axis, with it's position offset.