This is pretty simple actually, unless I'm mistaken you can try this script I concocted:
Code:
class Scene_Map
alias main_scene_map_collosalpokemon main
def main
main_scene_map_collosalpokemon
PUT YOUR IMAGE HERE
if Input.trigger?(Input::LT)
YOUR IMAGE.x+=32 # A tile's width
end
end
end
That theoretically should work, but remember to actually put the code for your own image in or else it'll do nothing guaranteed. This also only codes for if you press left (Which also happens to move the player left) so you'll have to add right, up, and down to complete it. I dunno if it's LT or LEFT for Pokemon essentials though, because I'm using a different Input Module, but it should be either LT or LEFT for you.