AKVIS Pastel supports the Batch Processing feature that lets you automatically convert a series of images with the same settings and saves you time and efforts. It is useful when creating a number of illustrations at the same style for a booklet or when processing all frames of video.
Even if you've never used this feature before it is simple to learn!
If you use the standalone version of AKVIS Pastel, read the instructions here.
If you use the Pastel plugin in Photoshop, use this tutorial.