fix thumbnails (#859)

* fix thumbnails

* thumnails

Author: dks333

docs.json

@@ -20,12 +20,7 @@
         "groups": [
           {
             "group": "Getting started",
-            "pages": [
-              "index",
-              "quickstart",
-              "installation",
-              "editor"
-            ]
+            "pages": ["index", "quickstart", "installation", "editor"]
           },
           {
             "group": "Core configuration",
@@ -91,14 +86,14 @@
                 "group": "MDX",
                 "icon": "markdown",
                 "pages": [
-                "api-playground/mdx/configuration",
-                "api-playground/mdx/authentication"
+                  "api-playground/mdx/configuration",
+                  "api-playground/mdx/authentication"
                 ]
               },
               "api-playground/troubleshooting"
             ]
           },
-          { 
+          {
             "group": "Authentication and personalization",
             "pages": [
               "authentication-personalization/overview",
@@ -139,7 +134,6 @@
                   "advanced/dashboard/sso",
                   "advanced/dashboard/permissions",
                   "advanced/dashboard/roles"
-
                 ]
               },
               "guides/deployments",
@@ -200,7 +194,7 @@
           {
             "group": "Version control and CI/CD",
             "pages": [
-            "settings/github",
+              "settings/github",
               "settings/gitlab",
               "settings/ci",
               "settings/preview-deployments"
@@ -215,9 +209,7 @@
         "groups": [
           {
             "group": "API Reference",
-            "pages": [
-              "api-reference/introduction"
-            ]
+            "pages": ["api-reference/introduction"]
           },
           {
             "group": "Admin",
@@ -242,9 +234,7 @@
         "groups": [
           {
             "group": "Changelog",
-            "pages": [
-              "changelog"
-            ]
+            "pages": ["changelog"]
           }
         ]
       }
@@ -348,16 +338,11 @@
       }
     ]
   },
-  "thumbnail": {
-    "background": "/thumbnail/background.png"
+  "thumbnails": {
+    "background": "/images/thumbnail/background.svg"
   },
   "contextual": {
-    "options": [
-      "copy",
-      "view",
-      "chatgpt",
-      "claude"
-    ]
+    "options": ["copy", "view", "chatgpt", "claude"]
   },
   "redirects": [
     {