Animated Fog

Hey, this is more a request really than an actual suggestion, but maybe someone will be able to help me out here,pehraps someone with awesome video editing skills. I am looking for 10MB file of a transparent fog rolling through. Because of it being fog it could ptentially be low res or a relatively short loop. I think it would be an absolutely amazing effect for maps in roll20. Does anyone have something like that?

To do this right, you'd need to create a seamless animated tile using alpha blending.  Right now, alpha blending isn't available for user uploaded images, but there might be a solution to that in the near future, at which point it would be possible to do this really, really well.