开发for循环代码，一次只实例化3个数组对象

所以我有一些代码来创建一个动态图库，创建一个文件位置的主数组，一个加载器协同程序，将图像加载到纹理和一个函数来实例化一个预制，该预制采用纹理，将其添加为精灵，然后相应地父预制。最后，for循环重复这个过程，直到我运行了整个文件数组，并用所有图像填充了我的图库。这适用于小型图库，但随着我的图库的增长，它可能变得笨拙，并开始占用大量内存。我的问题是我如何去修改这段代码，一次只加载3个图像(左，中，右)?我已经得到了我所有的图像在一个滚动容器，我想能够知道当图像滑离屏幕作为信号加载下一个(或上一个)。有没有人做过这个，不介意分享一点代码?

public Texture2D tex;
public string[] galleryImages;
GameObject galleryThumbHolder;
string[] arctopithecusImages;
string[] arctopithecusPNGImages;
string[] gulonImages;
string[] scythianWolfImages;
string[] simivulpaImages;
string[] succorathImages;
string[] tatusImages;
int currentIndex = 0;
// Create a master Array of all image files located in all Image locations
void Start()
{
    // Build Gallery Arrays
    arctopithecusImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/ARCTOPITHECUS/", "*.jpg");
    arctopithecusPNGImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/ARCTOPITHECUS/", "*.png");
    gulonImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/GULON/", "*.jpg");
    scythianWolfImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/SCYTHIAN-WOLF/", "*.png");
    simivulpaImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/SIMIVULPA/", "*.png");
    succorathImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/SUCCORATH/", "*.png");
    tatusImages = Directory.GetFiles(@"/Users/kenmarold/Screenshots/TATUS/", "*.png");
    // Concatenate all Folder Array into single Array
    galleryImages = 
        arctopithecusImages.Concat(arctopithecusPNGImages)
            .Concat(gulonImages)
            .Concat(scythianWolfImages)
            .Concat(simivulpaImages)
            .Concat(succorathImages)
            .Concat(tatusImages)
            .ToArray();
    for(int i = 0; i < galleryImages.Length; i++)
    {
        StartCoroutine("loader", currentIndex);
        currentIndex++;
    }
}
IEnumerator loader(int indexNum)
{
    WWW www = new WWW("file://" + galleryImages[indexNum]);         // get the first file from disk
    yield return www;                                               // Wait unill its loaded
    tex = new Texture2D(512,512);                                   // create a new Texture2D
    www.LoadImageIntoTexture(tex);                                  // put the image file into the new Texture2D
    createGalleryImages(tex);
}
public void createGalleryImages(Texture2D tex)
{
    // Instantiate Gallery Thumb Prefab and Load in Sprite
    //GameObject galleryThumb = Instantiate(Resources.Load("Prefabs/GalleryImageHolder")) as GameObject;
    GameObject galleryThumb = Instantiate(GameObject.FindGameObjectWithTag("GalleryImgHolder")) as GameObject;
    Image galleryImg = galleryThumb.GetComponent<Image>();
    Rect rct = new Rect(0, 0, tex.width, tex.height);               // Define Rect arg
    Vector2 pvt = new Vector2(0.5f, 0.5f);                          // Define Pivot arg
    galleryImg.sprite = Sprite.Create(tex, rct, pvt);
    // Set Gallery Thumb Parent
    galleryThumb.transform.SetParent(GameObject.FindGameObjectWithTag("GalleryThumbs").transform);
}