diff --git a/internal/js/esbuild/options.go b/internal/js/esbuild/options.go
index 32d2a6251..e5309fbbe 100644
--- a/internal/js/esbuild/options.go
+++ b/internal/js/esbuild/options.go
@@ -299,6 +299,15 @@ OUTER:
 			}
 			loaders[k] = loader
 		}
+	} else if opts.IsCSS {
+		loaders = make(map[string]api.Loader)
+		// For CSS builds, default to the file loader for common static
+		// file extensions so that url() references are handled correctly
+		// even when resolved by ESBuild's native resolver.
+		// See #14619.
+		for _, ext := range defaultCSSFileLoaderExts {
+			loaders[ext] = api.LoaderFile
+		}
 	}
 
 	mediaType := opts.MediaType
@@ -467,16 +476,14 @@ func (o Options) loaderFromFilename(filename string) api.Loader {
 		if found {
 			return l
 		}
-		// For CSS builds, handling, default to the file loader for unknown extensions.
-		return api.LoaderFile
 	} else {
 		l, found := extensionToLoaderMapJS[ext]
 		if found {
 			return l
 		}
-	}
 
-	return api.LoaderJS
+	}
+	return api.LoaderDefault
 }
 
 func (opts *Options) validate() error {
diff --git a/internal/js/esbuild/resolve.go b/internal/js/esbuild/resolve.go
index e9cfa7f9b..3bdfda2da 100644
--- a/internal/js/esbuild/resolve.go
+++ b/internal/js/esbuild/resolve.go
@@ -62,6 +62,12 @@ var extensionToLoaderMapCSS = map[string]api.Loader{
 	".css": api.LoaderCSS,
 }
 
+// Common static file extensions that should use the file loader in CSS builds.
+var defaultCSSFileLoaderExts = []string{
+	".png", ".jpg", ".jpeg", ".gif", ".svg", ".webp", ".avif",
+	".woff", ".woff2", ".ttf", ".eot", ".otf",
+}
+
 // This is a common sub-set of ESBuild's default extensions.
 // We assume that imports of JSON, CSS etc. will be using their full
 // name with extension.
diff --git a/tpl/css/build_integration_test.go b/tpl/css/build_integration_test.go
index c294452b7..718357de4 100644
--- a/tpl/css/build_integration_test.go
+++ b/tpl/css/build_integration_test.go
@@ -270,10 +270,15 @@ func TestCSSBuildLoadersDefault(t *testing.T) {
 -- hugo.toml --
 -- assets/a/pixel.png --
 iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
+-- static/b/issue14619.png --
+iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
 -- assets/css/main.css --
 body {
   background-image: url("a/pixel.png");
 }
+div {
+  background-image: url("static/b/issue14619.png");
+}
 -- layouts/home.html --
 {{ with resources.Get "css/main.css"  }}
 {{ with . | css.Build (dict "minify" true)  }}
@@ -285,6 +290,8 @@ body {
 	b := hugolib.Test(t, files, hugolib.TestOptOsFs())
 	b.AssertFileContent("public/css/main.css", `./pixel-NJRUOINY.png`)
 	b.AssertFileExists("public/css/pixel-NJRUOINY.png", true)
+	b.AssertFileContent("public/css/main.css", `url("./issue14619-NJRUOINY.png")`)
+	b.AssertFileExists("public/css/issue14619-NJRUOINY.png", true)
 }
 
 func TestCSSBuildBootstrapFromNPM(t *testing.T) {