update basePath

next.config.ts

@@ -2,6 +2,7 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   /* config options here */
+  basePath: '/deepsite',
   webpack(config, options) {
     const { isServer } = options;
     config.module.rules.push({
@@ -13,7 +14,7 @@ const nextConfig: NextConfig = {
           options: {
             limit: config.inlineImageLimit,
             fallback: require.resolve("file-loader"),
-            publicPath: `${config.assetPrefix}/_next/static/images/`,
+            publicPath: `${config.assetPrefix || '/deepsite'}/_next/static/images/`,
             outputPath: `${isServer ? "../" : ""}static/images/`,
             name: "[name]-[hash].[ext]",
             esModule: config.esModule || false,