![1990s_(style) 3girls age_difference animated animated_gif arms_up bangs beamed_sixteenth_notes black_hair blush bow braid child clock_tower_(series) clock_tower_the_first_fear dancing door eighth_note embarrassed fukuzawa_yumi full-face_blush hair_bow long_hair lowres maria-sama_ga_miteru multiple_girls musical_note ogasawara_sachiko open_door parody pixel_art running school_uniform serafuku shimazu_yoshino shoes short_hair short_twintails single_braid socks translated twintails walk-in rating:s score:7 post #12583](/cdn_image/preview/f2/5e/f25e0260d2671b24f4e65ef2a4540426.jpg)
This tag indicates that an image exhibits a distictive pixelized style (e.g. jagged edges, dithering). This may be either intentional or as a restriction on the software used to render it. This is common in older GIF images as well as images meant to invoke game sprites.
Pixel art is almost necessarily digital art in a rasterized format, and as such is naturally mutually exclusive with traditional media and vector traces.
Different from oekaki which is a very specific concept.