Unity运行时动态加载本地图片的方法，直接上代码，里面很详细。

using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;
using UnityEngine.UI;
 
public class Test : MonoBehaviour {
 
    public Image image;
    string localPath = @"D:\Sprites";       //图片存放的文件夹名
    FileInfo[] files;
    int index = 0;      //图片索引
 
 
    void Start () {
 
        //File.Exists(localPath) ： 判断某个目录下是否存在某个文件
        //判断是否存在某个文件夹
        if (Directory.Exists(localPath))
        {
            DirectoryInfo direction = new DirectoryInfo(localPath);
            files = direction.GetFiles("*");        //加载什么类型的文件
            Debug.Log(files.Length);
 
            //localPath + "/" + files[index].Name   : 用于得到文件的路径
 
            //StartCoroutine(Load(localPath + "/" + files[index].Name));
            LoadByIo(localPath + "/" + files[index].Name);
        }
 
    }
    
    void Update () {
        
    }
 
    /// <summary>
    /// 使用www加载
    /// </summary>
    /// <param name="url"></param>
    /// <returns></returns>
    IEnumerator Load(string url)
    {
        double startTime = (double)Time.time;
        //请求WWW
        WWW www = new WWW(url);
 
        yield return www;
        if (www != null && string.IsNullOrEmpty(www.error))
        {
            //获取Texture
            Texture2D texture = www.texture;
 
            //创建Sprite
            Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
            image.sprite = sprite;
 
            startTime = (double)Time.time - startTime;
            Debug.Log("www加载用时 ： " + startTime);
 
        }
    }
 
 
    /// <summary>
    /// 以IO方式进行加载
    /// </summary>
    private void LoadByIo(string url)
    {
        double startTime = (double)Time.time;
        //创建文件读取流
        FileStream fileStream = new FileStream(url, FileMode.Open, FileAccess.Read);
        //创建文件长度缓冲区
        byte[] bytes = new byte[fileStream.Length];
        //读取文件
        fileStream.Read(bytes, 0, (int)fileStream.Length);
 
        //释放文件读取流
        fileStream.Close();
        //释放本机屏幕资源
        fileStream.Dispose();
        fileStream = null;
 
        //创建Texture
        int width = 300;
        int height = 372;
        Texture2D texture = new Texture2D(width, height);
        texture.LoadImage(bytes);
 
        //创建Sprite
        Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
        image.sprite = sprite;
 
        startTime = (double)Time.time - startTime;
        Debug.Log("IO加载" + startTime);
 
    }
 
}

https://blog.csdn.net/qq_38721111/article/details/90711710