In electronic music terms, Shier's app functions partly as a filter, partly as a delay unit. A stationary image is sliced into pixels-wide bands; when you move your cursor the bands become "echoes" of the original image in the form of hundreds of micro-offsets. These create blurry trails with varying degrees of overlap, depending on how much you move the cursor. It's more complex but that's the basic idea.
Manning's recent images consist of touchscreen paintings with menu-selected brushes, textures and hues; am guessing these are "augmented finger paintings" and not done with a stylus. He has made them on the iPad as well as with Windows 8 demo screens inside the Microsoft Store [alien country for the Apple-brainwashed creative elite -- obligatory dig --ed.]. The buildup of color, washes, and calligraphic line in digital gesture painting can be seductive but let's remember the original AbEx artists also employed cinematic scale, gloppy physical media, and the athleticism of pushing the glop around with long-handled brushes. They would have laughed to see people making micro-movements on a TV screen and then saving them as jpegs and PNGs. The "action painting" model has been pretty thoroughly discredited but those are the reasons it's in museums, at any rate. Am possibly more interested in Manning's steady output of tiny de Kooningesque and Twomblyesque color-spasms as performance-cum-notation having to do with "available technology" and the instant masterpieces "apps" promise to deliver than some electronic de-reification of the earnest Real of gestural abstraction, although both motivations might be present. Also they are pretty, and it's always good to annoy the Marxist art-as-hair-shirt crowd.