doc: fix capitalization and image alt attributes (#4008)

Remove unneeded blank line
diff --git a/CODE_STYLE.md b/CODE_STYLE.md
index c20f73b..9543215 100644
--- a/CODE_STYLE.md
+++ b/CODE_STYLE.md
@@ -21,7 +21,7 @@
 #
 -->
 
-## indentation
+## Indentation
 
 Use 4 spaces as an indent:
 
diff --git a/LICENSE b/LICENSE
index 1e50066..0474b54 100644
--- a/LICENSE
+++ b/LICENSE
@@ -216,4 +216,3 @@
 The text of each license is the standard Apache 2.0 license.
 
    ewma.lua file from kubernetes/ingress-nginx: https://github.com/kubernetes/ingress-nginx Apache 2.0
-
diff --git a/README.md b/README.md
index 8272281..f85b6d7 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,7 @@
 
 The technical architecture of Apache APISIX:
 
-![](docs/assets/images/apisix.png)
+![Technical architecture of Apache APISIX](docs/assets/images/apisix.png)
 
 ## Community
 
diff --git a/docs/es/latest/README.md b/docs/es/latest/README.md
index bdbedc6..975bc7c 100644
--- a/docs/es/latest/README.md
+++ b/docs/es/latest/README.md
@@ -36,7 +36,7 @@
 
 La arquitectura técnica de Apache APISIX:
 
-![](../../assets/images/apisix.png)
+![La arquitectura técnica de Apache APISIX](../../assets/images/apisix.png)
 
 ## Communidad
 
diff --git a/docs/zh/latest/README.md b/docs/zh/latest/README.md
index 641dcba..88f2718 100644
--- a/docs/zh/latest/README.md
+++ b/docs/zh/latest/README.md
@@ -34,7 +34,7 @@
 
 Apache APISIX 的技术架构如下图所示:
 
-![](../../assets/images/apisix.png)
+![Apache APISIX 的技术架构](../../assets/images/apisix.png)
 
 ## 社区
 
diff --git a/kubernetes/README.md b/kubernetes/README.md
index 0afc71c..da88532 100644
--- a/kubernetes/README.md
+++ b/kubernetes/README.md
@@ -17,7 +17,7 @@
 #
 -->
 
-### kubernetes
+### Kubernetes
 
 There are some yaml files for deploying apisix in Kubernetes.
 
@@ -35,7 +35,7 @@
 $ kubectl create configmap apisix-gw-config.yaml --from-file=../conf/config.yaml
 ```
 
-#### when using etcd-operator
+#### When using etcd-operator
 
 when using etcd-operator, you need to change `apisix-gw-config-cm.yaml`: