diff --git a/package-lock.json b/package-lock.json
index 0380ebb..409460e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -32,7 +32,6 @@
         "morgan": "1.10.0",
         "pbf": "4.0.1",
         "pmtiles": "3.0.7",
-        "pngjs": "^7.0.0",
         "proj4": "2.12.1",
         "sanitize-filename": "1.6.3",
         "sharp": "0.33.5",
diff --git a/package.json b/package.json
index ffd207d..4c6bda2 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,6 @@
     "morgan": "1.10.0",
     "pbf": "4.0.1",
     "pmtiles": "3.0.7",
-    "pngjs": "^7.0.0",
     "proj4": "2.12.1",
     "sanitize-filename": "1.6.3",
     "sharp": "0.33.5",
diff --git a/src/contour.js b/src/contour.js
index d9cb768..82e774d 100644
--- a/src/contour.js
+++ b/src/contour.js
@@ -1,7 +1,6 @@
 import sharp from 'sharp';
 import mlcontour from '../node_modules/maplibre-contour/dist/index.mjs';
 import { getPMtilesTile } from './pmtiles_adapter.js';
-import { PNG } from 'pngjs';
 
 /**
  * Manages local DEM (Digital Elevation Model) data using maplibre-contour.