XV has the ability to run a number of standard image-processing algorithms on the current image. Algorithms are chosen via the Algorithms menu, and are executed immediately. Algorithms are cumulative, in that if you run an algorithm on an image, and then run a second algorithm, the second algorithm operates on the modified image produced by the first algorithm, and so on.
Blur (3x3): Runs a convolution over each plane (red, green, blue) of the image, using a 3x3 convolution mask consisting of all 1's. It has the effect of replacing each pixel in the image with the mean value of it and its immediate, 8-connected neighbors.
Blur (5x5): Like Blur (3x3), only it uses a 5x5 convolution mask of all 1's. Blurs the image more than the 3x3 version.
Blur (7x7): Uses a 7x7 mask of all 1's. Blurs the image more than the 5x5 version does.
Edge Detection: Runs a convolution using a 3x3 mask that detects vertical edges and a 3x3 mask that detects horizontal edges. The two masks are added together so that the complete edge detection can be done in just one convolution. The convolution is done separately for each plane (red, green, blue) of the image.
Emboss: Runs an algorithm that produces `embossed' images by using a variation of the edge detection algorithm. It produces greyscale (8-bit) images where most of the image is shown as a medium gray. `Leading' edges (edges found on the top and left sides) are shown as a lighter gray, and `trailing' edges (bottom and right edges) are shown as a darker gray.
Oil Painting: Does an `oil transfer', as described in the book "Beyond Photography", by Holzman. The basic algorithm is to take a 7x7 rectangle centered around the current pixel, compute a histogram of these (49) pixels, and replace the current pixel with the `most popular' pixel as determined by the histogram.