diff --git a/lib/ext/render.js b/lib/ext/render.js
index cac22db..c16b60d 100644
--- a/lib/ext/render.js
+++ b/lib/ext/render.js
@@ -152,10 +152,10 @@ exports.requireExt = function(display, callback)
             }
 
             ext.FreePicture = function(pid) {
-                X.seq_num++;
-                X.pack_stream.pack('CCSL', [ext.majorOpcode, 7, 2, pid]);
-                X.pack_stream.flush();
-            }
+              X.seq_num++;
+              X.pack_stream.pack('CCSL', [ext.majorOpcode, 7, 2, pid]);
+              X.pack_stream.flush();
+            };
 
             function floatToFix(f)
             {
@@ -163,23 +163,42 @@ exports.requireExt = function(display, callback)
             }
 
             // see example of blur filter here: https://github.com/richoH/rxvt-unicode/blob/master/src/background.C
-            // TODO: not ready yet.
             ext.SetPictureFilter = function(pid, name, filterParams)
             {
+                if (filterParams === 0)
+                  filterParams = [0];
+                if (!filterParams)
+                  filterParams = [];
+                if (!Array.isArray(filterParams))
+                  filterParams = [filterParams];
+
                 X.seq_num++;
-                var reqLen = 2;  //header + params + 1xStopfix+2xColors
-                var format = 'CCSLa';
-                var params = [ext.majorOpcode, 30, reqLen, pid];
-                /*
-                if (name == 'convolution')
-                {
-                    reqLen += 2;
-                    format += 'L';
-                    params.push(floatToFix(filterParams));
+                var reqLen = 2;
+                var format = 'CCSLSxxp';
+                var params = [ext.majorOpcode, 30, reqLen, pid, name.length, name + '\0'];
+                reqLen += xutil.padded_length(name.length+3)/4 + filterParams.length;
+
+                if (name == 'nearest' || name == 'bilinear' || name == 'fast' || name == 'good' || name == 'best') {
+                  if (filterParams.length != 0) {
+                    throw 'Render.SetPictureFilter: "' + name + '" - unexpected parameters for filters";
+                  }
+                } else if (name == 'convolution' || ) {
+                   if (filterParams.length < 2 || filterParams[0]*filterParams[1] !== filterParams.length + 2) {
+                     throw 'Render.SetPictureFilter: "convolution" - incorrect matrix dimensions. Must be flat array [ w, h, elem1, elem2, ... ]';
+                   }
+                   for (var i=0; i < filterParams.length; ++i) {
+                      format += 'L';
+                      params.push(floatToFix(filterParams[i]));
+                   }
+                } else if (name == 'binomial' || name == 'gaussian') {
+                   if (filterParams.length < 2) {
+                     throw 'Render.SetPictureFilter: "' + name + '" - incorrect number of parameters, must be exactly 1 number, instead got: ' + filterParams;
+                   }
+                  format += 'L';
+                  params.push(floatToFix(filterParams[0]));
                 } else {
-                    throw 'Not implemented filter ' + name;
+                    throw 'Render.SetPictureFilter: unknown filter "' + name + '"';
                 }
-                */
                 params[2] = reqLen;
                 X.pack_stream.pack(format, params);
                 X.pack_stream.flush();