diff --git a/HISTORY.md b/HISTORY.md
index 99bcf59..6a3b46a 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,5 +1,8 @@
 # Release history
 
+## v0.1.7
+Changed fileGroups option from array of file names to regular expression
+
 ## v0.1.6
 Updated dependencies
 
diff --git a/lib/CanvasRenderer/FILTERS.js b/lib/CanvasRenderer/FILTERS.js
index 95efe1a..abd9393 100644
--- a/lib/CanvasRenderer/FILTERS.js
+++ b/lib/CanvasRenderer/FILTERS.js
@@ -1,7 +1,5 @@
 'use strict';
 
-var Canvas = require('canvas');
-
 // TODO:
 // - bevel filter
 // - gradient glow filter
diff --git a/lib/CanvasRenderer/SwfImgRenderer/PngWriter.js b/lib/CanvasRenderer/SwfImgRenderer/PngWriter.js
index 986b305..762fa40 100644
--- a/lib/CanvasRenderer/SwfImgRenderer/PngWriter.js
+++ b/lib/CanvasRenderer/SwfImgRenderer/PngWriter.js
@@ -71,6 +71,7 @@ PngWriter.prototype._addChunk = function (name, data, len) {
 	var buf = new Buffer(len + 12, 'binary');
 	buf.writeUInt32BE(len, 0);
 	buf.write(name, 4, 4);
+	// console.log('chunk type', name, JSON.stringify(data));
 	if (typeof data !== 'string') {
 		data.copy(buf, 8, 0, len);
 	} else { 
diff --git a/lib/CanvasRenderer/SwfImgRenderer/index.js b/lib/CanvasRenderer/SwfImgRenderer/index.js
index 608e075..e36352f 100644
--- a/lib/CanvasRenderer/SwfImgRenderer/index.js
+++ b/lib/CanvasRenderer/SwfImgRenderer/index.js
@@ -21,7 +21,6 @@ SwfImgRenderer.prototype._renderPng = function (swfObject, whenDone) {
 		// Should never happen unless caller is wrong
 		throw new Error('Invalid data for PNG file');
 	}
-
 	var self = this;
 	this._inflate(swfObject.colorData, function (buffer) {
 		swfObject.data = buffer;
diff --git a/lib/CanvasRenderer/main.js b/lib/CanvasRenderer/main.js
index 10b3729..da0a5ed 100644
--- a/lib/CanvasRenderer/main.js
+++ b/lib/CanvasRenderer/main.js
@@ -2,22 +2,30 @@
 var SwfImgRenderer  = require('./SwfImgRenderer/index');
 
 /* List of known issues:
-
 	- drawImage does implicit conversion of image position to integer
 	(due to node canvas, issue #395 on https://github.com/LearnBoost/node-canvas)
+
 	- Global Composite Operations Bug: source-in can result in an overflow if rendered image is bigger than the mask
 	(due to node canvas, issue #416 on https://github.com/LearnBoost/node-canvas)
+
+	- Global Composite Operations Bug (Another): source-in can result in dark outlines of the image when rotated
+	(due to node canvas, not reported)
+
 	- Alpha of gradient fill style bug
 	(due to node canvas, issue #417 on https://github.com/LearnBoost/node-canvas)
+
 	- Drawing images of dimension (w, h) = (0, 0) or with a scale of 0 makes a canvas unsuable
 	(due to node canvas, not reported)
-	- Another Global Composite Operations Bug: source-in can result in dark outlines of the image when rotated
-	(due to node canvas, not reported)
+
 	- putImageData does not always use the last updated data
 	(seems to be due to node canvas, not reported)
 
+	- Path point positions need to be rounded to one decimal value when creating a vectorial path
+	(due to node canvas, not reported)
+
 	- When rendering images the size of the canvas could be too small if glows or shadows are being applied
 		(Fix: consider glow and shadow dimensions when setting canvas dimension, increased dimension should be notified to the extractor)
+
 	- Not tested but probably does not work: rendering rotated shapes with an alpha blend mode will not have the same result as in flash
 */
 
diff --git a/lib/CanvasRenderer/prepareImages.js b/lib/CanvasRenderer/prepareImages.js
index c958850..dc30606 100644
--- a/lib/CanvasRenderer/prepareImages.js
+++ b/lib/CanvasRenderer/prepareImages.js
@@ -25,7 +25,7 @@ CanvasRenderer.prototype._prepareImages = function () {
 
 			imageContext.drawImage(img, 0, 0, img.width, img.height);
 		} else {
-			console.warn('[CanvasRenderer.prepareImages] Image is empty', imageData.id);
+			console.warn('[CanvasRenderer.prepareImages] Image is empty', imageData.id, JSON.stringify(imageBuffer));
 		}
 
 		nImagesReady += 1;
diff --git a/lib/CanvasRenderer/renderImages.js b/lib/CanvasRenderer/renderImages.js
index f627735..4373c84 100644
--- a/lib/CanvasRenderer/renderImages.js
+++ b/lib/CanvasRenderer/renderImages.js
@@ -152,7 +152,7 @@ function getGraphicsToRender(symbols, symbolList, images) {
 	}
 	return graphics;
 }
-
+var nBytes = 0;
 CanvasRenderer.prototype._renderGraphics = function (graphics, graphicDims, canvasses) {
 	for (var id in graphics) {
 		var canvas  = new Canvas();
@@ -163,6 +163,7 @@ CanvasRenderer.prototype._renderGraphics = function (graphics, graphicDims, canv
 
 		canvas.width  = dimensions.sw;
 		canvas.height = dimensions.sh;
+		nBytes += canvas.width * canvas.height * 4;
 
 		if (graphic.isShape) {
 			var transform = [dimensions.ratio, 0, 0, dimensions.ratio, - dimensions.dx, - dimensions.dy];
@@ -320,8 +321,8 @@ CanvasRenderer.prototype._renderImages = function (retry) {
 		if (atlas) {
 			imageList = [{ img: atlas, name: 'atlas' }];
 		} else {
-			// TODO: add an option to let the user choose whether he wants to create several
-			// several atlas or reduce the asset sizes when this situation happens
+			// TODO: add an option to let the user choose whether he wants to create
+			// several atlases or reduce the asset sizes when this situation happens
 
 			// Atlas could not be extracted at current ratio
 			// Reducing extraction ratio and attempting rendering once more
diff --git a/lib/CanvasRenderer/vectorialRendering.js b/lib/CanvasRenderer/vectorialRendering.js
index 98ba554..a2e0fc0 100644
--- a/lib/CanvasRenderer/vectorialRendering.js
+++ b/lib/CanvasRenderer/vectorialRendering.js
@@ -186,6 +186,7 @@ CanvasRenderer.prototype._drawShapes = function (shapes, canvas, context, transf
 	}
 };
 
+// Due to a bug in cairo, path point positions have to be rounded
 CanvasRenderer.prototype._createPath = function (context, shapes, transform, pixelHinting) {
 	context.beginPath();
 	var p, seg;
@@ -238,7 +239,6 @@ CanvasRenderer.prototype._outlineShapes = function (context, shapes, transform,
 	this._createPath(context, shapes, transform, pixelHinting);
 
 	var s, color, alpha, scale;
-
 	context.save();
 
 	if (line.capStart) {
diff --git a/lib/Gordon/parser.js b/lib/Gordon/parser.js
index 9cf2138..973e606 100644
--- a/lib/Gordon/parser.js
+++ b/lib/Gordon/parser.js
@@ -1,4 +1,4 @@
-//See http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/swf/pdf/swf-file-format-spec.pdf
+// See http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/swf/pdf/swf-file-format-spec.pdf
 
 'use strict';
 
@@ -8,7 +8,7 @@ var Stream = require('./stream.js');
 function SwfParser() {}
 module.exports = SwfParser;
 
-// TODO: figure out if we cannot get rid of this 'nlizeMatrix' function
+// TODO: figure out if we can get rid of this 'nlizeMatrix' function
 function nlizeMatrix(matrix) {
 	return {
 		scaleX: matrix.scaleX * 20,
@@ -62,7 +62,6 @@ SwfParser.prototype = {
 		} else if (sign === signatures.SWF) {
 			this._parseSwf(stream, cb);
 		} else {
-			console.log('youhou!!');
 			cb('Invalid SWF file: ' + swfName);
 		}
 	},
@@ -75,9 +74,9 @@ SwfParser.prototype = {
 	// to extract regular swf files.
 	// It should possible to determine the symbols of the swl table from the dofus database
 
-	//Special table at the head of a ".swl" file; we did not find why this is useful...
-	//Maybe to be able to easily look for which symbols are defined in a .swf without
-	//having to parse/decompress it all.
+	// Special table at the head of a ".swl" file; we did not find why this is useful...
+	// Maybe to be able to easily look for which symbols are defined in a .swf without
+	// having to parse/decompress it all.
 	_readSwlTable: function (stream) {
 		var sign = stream.readString(2);
 		if (sign[0] !== 'L' || sign.charCodeAt(1) !== 0) {
@@ -771,8 +770,8 @@ SwfParser.prototype = {
 		var depth        = stream.readUI16();
 		var hasCharacter = flags  & f.HAS_CHARACTER;
 		var hasImage     = flags2 & f.HAS_IMAGE;
-		var className    = ((flags2 & f.HAS_CLASS_NAME) || (hasImage && hasCharacter)) ? stream.readString : undefined;
-		var character    = { depth: depth };
+		var baseClass    = ((flags2 & f.HAS_CLASS_NAME) || (hasImage && hasCharacter)) ? stream.readString : undefined;
+		var character    = { depth: depth, baseClass: baseClass };
 
 		if (hasCharacter) {
 			var objId = stream.readUI16();
diff --git a/lib/Helper/generateExportList.js b/lib/Helper/generateExportList.js
index 8349678..ab9526c 100644
--- a/lib/Helper/generateExportList.js
+++ b/lib/Helper/generateExportList.js
@@ -121,15 +121,29 @@
 // }
 
 
-function generateExportList(symbols, classList) {
+function generateExportList(symbols, classList, attributeFilter) {
 	var symbolList = [];
 
+	// Creating list of symbols to export
+	// Starting with the symbols corresponding to the class to export
 	var symbolsToVisit = [];
 	for (var className in classList) {
 		var classId = classList[className];
-		symbolsToVisit.push(classId);
+
+		if (attributeFilter) {
+			var classSymbol = symbols[classId];
+			for (var a = 0; a < attributeFilter.length; a +=1) {
+				if (classSymbol[attributeFilter[a]]) {
+					// The class has the corresponding attribute, it is added for export
+					symbolsToVisit.push(classId);
+				}
+			}
+		} else {
+			symbolsToVisit.push(classId);
+		}
 	}
 
+	// Including symbols that are descendants of the classes to export
 	var visistedSymbols = {};
 	while (symbolsToVisit.length > 0) {
 		var symbolId = symbolsToVisit.pop();
diff --git a/lib/Helper/groupClasses.js b/lib/Helper/groupClasses.js
index a15b3fd..2603f7e 100644
--- a/lib/Helper/groupClasses.js
+++ b/lib/Helper/groupClasses.js
@@ -1,12 +1,11 @@
 'use strict';
 
 function groupClasses(classList, classGroups, split) {
-
-	// Grouping classes
 	if (!split && Object.keys(classGroups).length === 0) {
 		return [{ name: '', list: classList }];
 	}
 
+	// Creating list of classes that will be exported separately
 	var splitName;
 	var classSplits = {};
 	for (splitName in classGroups) {
@@ -14,12 +13,12 @@ function groupClasses(classList, classGroups, split) {
 	}
 
 	var className;
-	var remainingClasses = [];
+	var remainingClasses = []; // List of classes that will be exported together
 	for (className in classList) {
 		var matchFound = false;
 		for (splitName in classGroups) {
-			var splitRegEx = classGroups[splitName];
-			if (className.match(splitRegEx)) {
+			var groupRegEx = classGroups[splitName];
+			if (className.match(groupRegEx)) {
 				classSplits[splitName][className] = classList[className];
 				matchFound = true;
 			}
diff --git a/lib/Helper/makeFileGroups.js b/lib/Helper/groupFiles.js
similarity index 65%
rename from lib/Helper/makeFileGroups.js
rename to lib/Helper/groupFiles.js
index 55620b1..fd5ce3d 100644
--- a/lib/Helper/makeFileGroups.js
+++ b/lib/Helper/groupFiles.js
@@ -5,10 +5,10 @@ function getFileName(uri) {
 	return uri.substring(uri.lastIndexOf(separator) + 1, uri.lastIndexOf('.'));
 }
 
-function makeFileGroups(uris, fileGroups) {
+function groupFiles(uris, fileGroupsRegEx) {
 	var fileGroupsArray  = [];
 	var u, fileName;
-	if (!fileGroups) {
+	if (!fileGroupsRegEx) {
 		for (u = 0; u < uris.length; u += 1) {
 			fileName = getFileName(uris[u]);
 			fileGroupsArray.push({ input: [uris[u]], output: fileName });
@@ -16,30 +16,34 @@ function makeFileGroups(uris, fileGroups) {
 		return fileGroupsArray;
 	}
 
+	// Creating one group per file
 	var fileGroupsObject = {};
 	for (u = 0; u < uris.length; u += 1) {
 		fileName = getFileName(uris[u]);
 		fileGroupsObject[fileName] = [uris[u]];
 	}
 
-
 	var output;
-	for (output in fileGroups) {
-		var groupFiles = fileGroups[output];
+	for (output in fileGroupsRegEx) {
 		var fileGroup = fileGroupsObject[output];
 		if (fileGroup === undefined) {
 			fileGroup = [];
 			fileGroupsObject[output] = fileGroup;
 		}
 
-		for (var f = 0; f < groupFiles.length; f += 1) {
-			fileName = groupFiles[f];
+		var groupRegEx = fileGroupsRegEx[output]; // pattern of the current group
+		for (u = 0; u < uris.length; u += 1) {
+			fileName = getFileName(uris[u]);
 			if (fileName === output) {
+				// File name is identical to the output, therefore they are merged
 				continue;
 			}
-			var fileArray = fileGroupsObject[fileName];
-			if (fileArray) {
-				fileGroup.push(fileArray[0]);
+
+			// Merging file to group if it matches the pattern
+			if (fileName.match(groupRegEx)) {
+				fileGroup.push(uris[u]);
+
+				// Removing the file as a stand-alone
 				delete fileGroupsObject[fileName];
 			}
 		}
@@ -56,4 +60,4 @@ function makeFileGroups(uris, fileGroups) {
 
 	return fileGroupsArray;
 }
-module.exports = makeFileGroups;
\ No newline at end of file
+module.exports = groupFiles;
\ No newline at end of file
diff --git a/lib/Helper/index.js b/lib/Helper/index.js
index 7d82750..4cfa8f7 100644
--- a/lib/Helper/index.js
+++ b/lib/Helper/index.js
@@ -8,7 +8,7 @@ module.exports.getClasses               = require('./getClasses.js');
 module.exports.getMains                 = require('./getMains.js');
 module.exports.groupClasses             = require('./groupClasses.js');
 module.exports.filterClasses            = require('./filterClasses.js');
-module.exports.makeFileGroups           = require('./makeFileGroups.js');
+module.exports.groupFiles               = require('./groupFiles.js');
 module.exports.flattenAnimations        = require('./flattenAnimations.js');
 module.exports.simplifyAnimation        = require('./simplifyAnimation.js');
 module.exports.delocateMatrices         = require('./delocateMatrices.js');
\ No newline at end of file
diff --git a/lib/SwfObjectProcessor/createSymbols.js b/lib/SwfObjectProcessor/createSymbols.js
index 52b543d..ebf4fb9 100644
--- a/lib/SwfObjectProcessor/createSymbols.js
+++ b/lib/SwfObjectProcessor/createSymbols.js
@@ -27,7 +27,6 @@ function createSymbol(swfObject) {
 		break;
 
 	case 'shape':
-
 		var shapes = swfObject.edges;
 		var imagesArray  = [];
 		for (var s = 0; s < shapes.length; s += 1) {
diff --git a/lib/index.js b/lib/index.js
index 5f98d80..4327969 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -48,7 +48,6 @@ function Jeff() {
 	this._classGroupName         = undefined; // Name
 	this._classGroupList         = undefined; // Classes
 	this._hierarchy              = undefined; // Hierarchy of the symbols
-
 }
 
 function JeffOptions(params) {
@@ -86,6 +85,7 @@ function JeffOptions(params) {
 	this.classGroups       = params.classGroups       || {};
 	this.fileGroups        = params.fileGroups        || {};
 	this.fileGroupRatios   = params.fileGroupRatios   || {};
+	this.attributeFilter   = params.attributeFilter;
 	this.classRatios       = params.classRatios;
 	this.container         = params.container;
 	this.ignoreExpression  = params.ignoreExpression;
@@ -147,7 +147,7 @@ Jeff.prototype._extractFileGroups = function (swfUris, endExtractionCb) {
 	var nbFiles  = 0;
 	var nbErrors = 0;
 
-	var filesPerGroup = helper.makeFileGroups(swfUris, this._options.fileGroups);
+	var filesPerGroup = helper.groupFiles(swfUris, this._options.fileGroups);
 	console.log('Starting conversion of', swfUris.length, 'file(s)');
 
 	var self = this;
@@ -274,7 +274,7 @@ Jeff.prototype._processFileGroup = function (nextGroupCb) {
 		function (classGroup, nextClassListCb) {
 			self._classGroupName = classGroup.name;
 			self._classGroupList = classGroup.list;
-			self._symbolList = helper.generateExportList(self._symbols, self._classGroupList);
+			self._symbolList = helper.generateExportList(self._symbols, self._classGroupList, self._options.attributeFilter);
 			self._renderer.renderSymbols(self,
 				function (imageList, graphicProperties) {
 					self._extractClassGroup(imageList, graphicProperties, nextClassListCb);
@@ -303,7 +303,7 @@ Jeff.prototype._generateImageName = function (imgName) {
 	if (this._options.exportAtRoot) {
 		imgPath = path.basename(imgPath);
 	}
-	
+
 	return path.join(this._options.outDir, imgPath + '.png');
 };
 
diff --git a/package.json b/package.json
index 110702c..710bec6 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
 	"name": "jeff",
 	"description": "Extracts Json meta-data and images from a SWF Flash file.",
-	"version": "0.1.6",
+	"version": "0.1.7",
 	"private": false,
 	"author": {
 		"name": "Brice Chevalier",