void load_image_buffer(const DVector<uint8_t>& p_buffer, uint8_t type);

New API: load_image_buffer

ImageTexture load_image_buffer from a ByteArray

GDScript Example:

func _init():
    var file = File.new()
    file.open("res://test.png",1) # 0 == .jpg  1 == .png 2 == .webp
    var db = file.get_buffer(file.get_len())
    file.close()
    var img = ImageTexture.new()
    img.set_flags(0)
    img.load_image_buffer(db,1)
    var sprite = Sprite.new()
    sprite.set_texture(img)
    sprite.set_centered(false)
    get_root().add_child(sprite)