I am a student of computer science with interest in image processing. I have learned how to apply a few effects to images like making them grayscale, sketching them out of lines, etc.  I would like to learn more about the algorithmic techniques  behind creative manipulation of images like making them sepia-tone, smudging them, etc.  Can someone please point me in the right direction? How do I learn the fundamentals of these algorithms? 
Where can a student learn image processing?
reference request;image processing
There are books on digital image processing which you can look into. Many common image manipulation techniques, such as smudging (usually known as blurring) are accomplished by image filtering, which is a process of applying a two-dimensional filter to an image: the value of each pixel in the new image is a linear combination of its original value and the original values of its neighbors. Sepia tone is an example of color manipulation: assuming the image is stored as RGB, this amounts to applying some carefully constructed mapping on the R,G,B values of each pixel. The mapping can be represented as a table $\{0,\ldots,255\}^3 \to \{0,\ldots,255\}^3$, or alternatively some formula can be applied instead.