diff --git a/docs/notes/计算机网络 - 概述.md b/docs/notes/计算机网络 - 概述.md
index 99c795f9..827ae1ff 100644
--- a/docs/notes/计算机网络 - 概述.md	
+++ b/docs/notes/计算机网络 - 概述.md	
@@ -28,21 +28,21 @@
 
 互联网服务提供商 ISP 可以从互联网管理机构获得许多 IP 地址，同时拥有通信线路以及路由器等联网设备，个人或机构向 ISP 缴纳一定的费用就可以接入互联网。
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/7_2001550811502556.png" width="500"/> </div><br>
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/72be01cd-41ae-45f7-99b9-a8d284e44dd4.png" width="500"/> </div><br>
 
 目前的互联网是一种多层次 ISP 结构，ISP 根据覆盖面积的大小分为第一层 ISP、区域 ISP 和接入 ISP。互联网交换点 IXP 允许两个 ISP 直接相连而不用经过第三个 ISP。
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/8_2001550812038190.png" width="500"/> </div><br>
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/3be42601-9d33-4d29-8358-a9d16453af93.png" width="500"/> </div><br>
 
 # 主机之间的通信方式
 
 - 客户-服务器（C/S）：客户是服务的请求方，服务器是服务的提供方。
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/2_2001550810366269.png"/> </div><br>
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/914894c2-0bc4-46b5-bef9-0316a69ef521.jpg" width="240px"> </div><br>
 
 - 对等（P2P）：不区分客户和服务器。
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/3_2001550810442775.png"/> </div><br>
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/42430e94-3137-48c0-bdb6-3cebaf9102e3.jpg" width="200px"> </div><br>
 
 # 电路交换与分组交换
 
@@ -60,7 +60,7 @@
 
 总时延 = 排队时延 + 处理时延 + 传输时延 + 传播时延
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/4_2001550810732828.png" width="600"/> </div><br>
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/4b2ae78c-e254-44df-9e37-578e2f2bef52.jpg" width="380"/> </div><br>
 
 ## 1. 排队时延
 
@@ -74,7 +74,10 @@
 
 主机或路由器传输数据帧所需要的时间。
 
-<div align="center"><img src="https://latex.codecogs.com/gif.latex?delay=\frac{l(bit)}{v(bit/s)}"/></div> <br>
+<!-- <div align="center"><img src="https://latex.codecogs.com/gif.latex?delay=\frac{l(bit)}{v(bit/s)}"/></div> <br> -->
+
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/dcdbb96c-9077-4121-aeb8-743e54ac02a4.png" width="150px"> </div><br>
+
 
 其中 l 表示数据帧的长度，v 表示传输速率。
 
@@ -82,14 +85,15 @@
 
 电磁波在信道中传播所需要花费的时间，电磁波传播的速度接近光速。
 
-<div align="center"><img src="https://latex.codecogs.com/gif.latex?delay=\frac{l(m)}{v(m/s)}"/></div> <br>
+<!-- <div align="center"><img src="https://latex.codecogs.com/gif.latex?delay=\frac{l(m)}{v(m/s)}"/></div> <br> -->
+
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/a1616dac-0e12-40b2-827d-9e3f7f0b940d.png" width="150"> </div><br>
 
 其中 l 表示信道长度，v 表示电磁波在信道上的传播速度。
 
 # 计算机网络体系结构
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/f5d40b01-abf2-435e-9ce7-7889c41b2fa6.jpg" width="500"/> </div><br>
-
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/0fa6c237-a909-4e2a-a771-2c5485cd8ce0.png" width="450"/> </div><br>
 
 ## 1. 五层协议
 
@@ -119,7 +123,7 @@
 
 TCP/IP 体系结构不严格遵循 OSI 分层概念，应用层可能会直接使用 IP 层或者网络接口层。
 
-<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/6_2001550811175246.png" width="250"/> </div><br>
+<div align="center"> <img src="https://gitee.com/CyC2018/CS-Notes/raw/master/docs/pics/48d79be8-085b-4862-8a9d-18402eb93b31.png" width="250"/> </div><br>
 
 ## 4. 数据在各层之间的传递过程
 
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