The latest iOS client of Prisma got the new feature. Soon Android app also work smooth without internet connection.
Till now, when you tried to add photo effects to your photos, first of all Prisma uploading the photo to its cloud processing server, and downloading the processed photo to your device.
Processing on the cloud made the Prisma servers down number of times earlier. Keeping this in the mind, Prisma decided to process photos locally on the device itself. So now onwards you no need to maintain internet connection to add effects to your photos with Prisma app.
Every filter will be embedded into the core app, so Prisma app size may some what increase. But server issues no more hurt you. You can process unlimited photos locally on your device.
The processing time of every effect is completely depending on the processing power of your smartphone. Higher end phones can process the images bit faster than their lower end counterparts.