Stack Layers, no need to raster images to apply another instance of an already used filter or effect. Apply filters as a brush with edge blending such as feather applied with another filter used as a transition blending gradient like a manual ramp but simple for the user. I think users are demanding more features on their phones. Don't limit features. Allow for seedless compatibility with a workstation. You know it will get there eventually.

Could use many more features but I like yhe idea of filters that celebrities can upload. Would be nice yo stack layers or add more than one filter. Brush options to apply the filters would be fun.