Digital art drawn with attention to every individual pixel, normally with hard-edged tools. Often limited in color count, and frequently scaled up with nearest neighbour "interpolation" so you can see each individual pixel clearly (as in the first example below)
Generally low-resolution. If it's larger than 500x500 (without scaling), chances are it's pixel_(artwork), but could be oekaki or just plain digital_media_(artwork). If it contains many gradients, a similar principle may apply.
If you cannot distinguish each individual pixel clearly, it also may not be pixel_(artwork) Pixel art vs. binary drawings
Pixel art:
Careful attention is paid to the individual pixels.
Binary drawings:
Aliasing refers to hard changes between the colors of pixels with no smoothing (or "antialiasing").
When aliasing applies to the lineart of a drawing but the focus is not on the individual pixels, it is considered a binary drawing.
While these images have jagged, "pixelated" outlines, they do not have a particular focus on the individual pixels like pixel art does. Certain drawing programs like Microsoft Paint and those found on oekaki boards frequently result in images with aliased lineart. Media types: