The origins of images found on bootleg game boxes/carts

Now this is something I thought of bringing up a while back, but felt like there wasn't really enough to go on, but it's been kind of bugging me for a while now. Just where the heck do some of these bootleggers get their artwork from? I doubt that a lot of it is produced in-house by the bootlegger themselves, though some could be like that & even that would mean we'd have to track down the original bootlegger behind the artwork. Not much to really say since it's kind of hard to describe, other than they all come in wildly different art styles of sorts, ranging from 5 year old drawings to 70s/80s mecha anime to realistic images seemingly made with watercolor paint to weirdly modern looking takes on WW2 planes.
Here are some examples, all from Atari 2600 bootlegs & all taken from Atarimania:

www.atarimania.com/2600/boxes/hi_res/hili_ball_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/volleyball_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/banned_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/air_bone_assault_taiwan_v_case_cart.jpg
www.atarimania.com/2600/boxes/hi_res/marineflieger_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/super_ferrari_rainbow_vision_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/donkey_kong_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/pac_kong_quelle_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/netmaker_rainbow_vision_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/tennis_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/col_n_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/fortress_defense_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/pyramid_war_fantastic_game_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/burper_fantastic_game_cart.jpg
www.atarimania.com/2600/boxes/hi_res/curtiss_suntek_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/fire_bird_video_game_program_cart.jpg
www.atarimania.com/2600/boxes/hi_res/phantompanzer_ii_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/postman_tythm_softwares_cart.jpg
www.atarimania.com/2600/boxes/hi_res/megamania_tythm_softwares_cart.jpg
www.atarimania.com/2600/boxes/hi_res/ufo_patrol_taiwan_v_case_cart.jpg
www.atarimania.com/2600/boxes/hi_res/moto_cross_spacevision_cart.jpg
www.atarimania.com/2600/boxes/hi_res/smurf_digitel_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/spider_fighter_digitel_cart.jpg
www.atarimania.com/2600/boxes/hi_res/forest_hot_shot_french_cart.jpg
www.atarimania.com/2600/boxes/hi_res/frogger_taiwan_other_cart.jpg
www.atarimania.com/2600/boxes/hi_res/jawbreaker_tiger_vision_eram_cart.jpg
www.atarimania.com/2600/boxes/hi_res/solar_sea_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/2_in_1_patrol_back_strike_video_game_program_cart.jpg
www.atarimania.com/2600/boxes/hi_res/chinese_konfu_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/double_game_lilly_adventure_river_raid_ii_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/little_bear_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/laser_gate_spacevision_cart.jpg
www.atarimania.com/2600/boxes/hi_res/yars_attack_fantastic_game_cart.jpg
www.atarimania.com/game-atari-2600-vcs-sternkrieg_17454.html
www.atarimania.com/2600/boxes/hi_res/invasion_der_ufo_s_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/enduro_funvision_halley_s_comet_cart.jpg
www.atarimania.com/2600/boxes/hi_res/dragon_treasure_funvision_cart_3.jpg
www.atarimania.com/2600/boxes/hi_res/canival_ii_taiwan_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/der_vielfrass_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/tom_boy_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/turbo_home_video_computor_games_cart.jpg
www.atarimania.com/2600/boxes/hi_res/space_marshal_taiwan_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/galaxy_defender_taiwan_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/tutti_frutti_taiwan_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/ocean_city_defender_zellers_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/scorpion_fantastic_game_marpes_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/feuerwehr_im_einsatz_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/firebug_suntek_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/farmyard_fun_suntek_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/robin_hood_quelle_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/winterjagd_cart.jpg
www.atarimania.com/2600/boxes/hi_res/tuby_bird_suntek_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/ice_hockey_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/king_arthur_taiwan_cooper_black_cart.jpg
www.atarimania.com/2600/boxes/hi_res/catch_time_rainbow_vision_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/base_attack_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/beany_bopper_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/air_wolf_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/baseball_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/chess_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/bowling_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/fire_burg_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/karate_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/katastrophen_einsatz_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/128_in_1_space_ship_fighter_taiwan_exiting_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/32_in_1_enduro_ocean_city_taiwan_exciting_cart.jpg
www.atarimania.com/2600/boxes/hi_res/skai_dive_taiwan_cart.jpg
www.atarimania.com/2600/boxes/hi_res/squirrel_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/square_game_funvision_standard_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/super_man_taiwan_cooper_black_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/super_man_taiwan_game_cartridge_cart.jpg
www.atarimania.com/2600/boxes/hi_res/bermuda_suntek_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/round1_video_game_program_cart.jpg
www.atarimania.com/2600/boxes/hi_res/space_invader_fantastic_game_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/die_springteufel_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/spectracube_invasion_suntek_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/spectracube_taiwan_v_case_cart.jpg
www.atarimania.com/2600/boxes/hi_res/astrowar_star_master_taiwan_santa_claus_cart.jpg
www.atarimania.com/2600/boxes/hi_res/centipede_enduro_taiwan_astro_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/der_geheimkurier_cart_2.jpg
www.atarimania.com/2600/boxes/hi_res/dig_dug_unknown_taiwan_activision_cart.jpg
www.atarimania.com/2600/boxes/hi_res/2_in_1_keystone_patrol_guly_game_cart.jpg
www.atarimania.com/2600/boxes/hi_res/mafia_tythm_softwares_cart.jpg

Well, that does it for now. May add some more of these later on, but for now I'll be going to sleep because it's almost 3AM.