This finds all of the PNGs in a folder

loader.gd

extends Node

var image_db = {}

func _ready():
	image_db = load_pngs_from_directory("res://")
	print(image_db)

func load_pngs_from_directory(path):
    var files = {}
    var dir = Directory.new()
    dir.open(path)
    dir.list_dir_begin()

    while true:
        var file = dir.get_next()
        if file == "":
            break
        elif dir.current_is_dir() and not file.begins_with("."):
            print("getting sub folder: ", file)
            var sub_files = load_pngs_from_directory(path+"/"+file)
            if not sub_files.empty():
                files[file] = sub_files
        elif not file.begins_with(".") and file.ends_with(".png"):
            files[file] = load(path+"/"+file)

    dir.list_dir_end()

    return files