在使用序列帧之前需要准备好序列帧的图集，打图集的操作参考

[Unity UGUI图集系统]浅谈UGUI图集使用

准备好序列帧图集，序列帧的播放原理就是获取到图集中的所有图片，然后按照设置的速度按个赋值给Image，其余的都可以按照自己的需求加一些循环，是否设置原图大小等等功能

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI; public class UIImagAnimation : MonoBehaviour
 {
     public int Framerate = ;
     public bool IsLoop = true;
     public bool IsSetSnap = false;
     public string AtlasName = "";     private Sprite[] sprites;
     private int curIndex = ;
     private float curRate = ;
     private Image mImage;
     // Start is called before the first frame update
     void Start()
     {
         if (mImage == null) mImage = GetComponent<Image>();
         if (sprites == null) sprites = UIResourceLoadManager.Instance.LoadSprites(AtlasName, sprites);
     }     // Update is called once per frame
     void Update()
     {
         if (mImage != null && sprites != null && sprites.Length > )
         {
             if (curIndex < sprites.Length || IsLoop)
             {
                 curIndex %= sprites.Length;
                 curRate += Time.deltaTime;
                 if (curRate > ) curRate = ;
                 float tempRate = 1f / Framerate;
                 if (tempRate < curRate)
                 {
                     curRate = tempRate >  ? curRate - tempRate : ;
                     mImage.sprite = sprites[curIndex];
                     if (IsSetSnap) mImage.SetNativeSize();
                     curIndex++;
                 }
             }
         }
     }
 }

根据自己的需求设置好参数，一个简单的UGUI下的序列帧播放功能就实现了