Disable png quantization by default for now

docs/config.rst

@@ -20,9 +20,10 @@ Example::
         "127.0.0.1:8080"
       ],
       "formatQuality": {
-        "png": 90,
         "jpeg": 80,
-        "webp": 90
+        "webp": 90,
+        "pngQuantization": false,
+        "png": 90
       },
       "maxSize": 2048
     },
@@ -70,6 +71,8 @@ You can use this to optionally specify on what domains the rendered tiles are ac
 
 Quality of the compression of individual image formats. [0-100]
 
+The value for ``png`` is only used when ``pngQuantization`` is ``true``.
+
 ``maxSize``
 -----------
 

src/serve_rendered.js

@@ -317,9 +317,13 @@ module.exports = function(options, repo, params, id, dataResolver) {
           }
 
           if (format == 'png') {
-            buffer = pngquant.compress(buffer, {
-              quality: [0, formatQuality || 90]
-            });
+            var usePngQuant =
+                (options.formatQuality || {}).pngQuantization === true;
+            if (usePngQuant) {
+              buffer = pngquant.compress(buffer, {
+                quality: [0, formatQuality || 90]
+              });
+            }
           }
 
           res.set({