diff --git a/Gruntfile.js b/Gruntfile.js
index a7083ea6..08788558 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -177,6 +177,7 @@ module.exports = function(grunt) {
           {src: ['dest/js/piskel-packaged-min.js'], dest: 'dest/js/piskel-packaged-min' + version + '.js'},
           {src: ['src/logo.png'], dest: 'dest/logo.png'},
           {src: ['src/js/lib/iframeLoader-0.1.0.js'], dest: 'dest/js/lib/iframeLoader-0.1.0.js'},
+          {src: ['src/js/lib/gif/gif.ie.worker.js'], dest: 'dest/js/lib/gif/gif.ie.worker.js'},
           {expand: true, src: ['img/**'], cwd: 'src/', dest: 'dest/', filter: 'isFile'},
           {expand: true, src: ['css/fonts/**'], cwd: 'src/', dest: 'dest/', filter: 'isFile'},
           {expand: true, src: ['**/*.html'], cwd: 'src/', dest: 'dest/', filter: 'isFile'}
diff --git a/src/css/settings-export.css b/src/css/settings-export.css
index 8ad233c7..e6dd2fe9 100644
--- a/src/css/settings-export.css
+++ b/src/css/settings-export.css
@@ -18,11 +18,6 @@
   max-width:32px;
 }
 
-.png-export-preview {
-  margin:10px 0;
-  overflow: hidden;
-}
-
 .png-export-preview img {
   max-height:32px;
   float: left;
@@ -34,6 +29,11 @@
   margin-top: 10px;
 }
 
+.gif-upload,
+.png-export-preview {
+  overflow: hidden;
+}
+
 .gif-upload-status,
 .gif-export-preview {
   float : left;
diff --git a/src/css/style.css b/src/css/style.css
index dd8d48e4..16f7aa14 100644
--- a/src/css/style.css
+++ b/src/css/style.css
@@ -11,10 +11,6 @@ body {
   display: none;
 }
 
-.clearfix {
-  overflow: hidden;
-}
-
 .allow-user-select {
   -webkit-touch-callout: initial;
   -webkit-user-select: initial;
diff --git a/src/js/lib/gif/gif.worker.js b/src/js/lib/gif/gif.worker.js
index 44434d4d..296b21f3 100644
--- a/src/js/lib/gif/gif.worker.js
+++ b/src/js/lib/gif/gif.worker.js
@@ -3,13 +3,18 @@
 		(function(b){function a(b,d){if({}.hasOwnProperty.call(a.cache,b))return a.cache[b];var e=a.resolve(b);if(!e)throw new Error('Failed to resolve module '+b);var c={id:b,require:a,filename:b,exports:{},loaded:!1,parent:d,children:[]};d&&d.children.push(c);var f=b.slice(0,b.lastIndexOf('/')+1);return a.cache[b]=c.exports,e.call(c.exports,c,c.exports,f,b),c.loaded=!0,a.cache[b]=c.exports}a.modules={},a.cache={},a.resolve=function(b){return{}.hasOwnProperty.call(a.modules,b)?a.modules[b]:void 0},a.define=function(b,c){a.modules[b]=c},a.define('/gif.worker.coffee',function(d,e,f,g){var b,c;b=a('/GIFEncoder.js',d),c=function(a){var c,e,d,f;return c=new b(a.width,a.height),a.index===0?c.writeHeader():c.firstFrame=!1,c.setTransparent(a.transparent),c.setRepeat(a.repeat),c.setDelay(a.delay),c.setQuality(a.quality),c.setPreserveColors(a.preserveColors),c.addFrame(a.data),a.last&&c.finish(),d=c.stream(),a.data=d.pages,a.cursor=d.cursor,a.pageSize=d.constructor.pageSize,a.canTransfer?(f=function(c){for(var b=0,d=a.data.length;b<d;++b)e=a.data[b],c.push(e.buffer);return c}.call(this,[]),self.postMessage(a,f)):self.postMessage(a)},self.onmessage=function(a){return c(a.data)}}),a.define('/GIFEncoder.js',function(e,k,i,j){function c(){this.page=-1,this.pages=[],this.newPage()}function b(a,b){this.width=~~a,this.height=~~b,this.transparent=null,this.transIndex=0,this.repeat=-1,this.delay=0,this.image=null,this.pixels=null,this.indexedPixels=null,this.colorDepth=null,this.colorTab=null,this.usedEntry=new Array,this.palSize=7,this.dispose=-1,this.firstFrame=!0,this.sample=10,this.preserveColors=!1,this.out=new c}var f=a('/TypedNeuQuant.js',e),g=a('/SimpleQuant.js',e),h=a('/LZWEncoder.js',e);c.pageSize=4096,c.charMap={};for(var d=0;d<256;d++)c.charMap[d]=String.fromCharCode(d);c.prototype.newPage=function(){this.pages[++this.page]=new Uint8Array(c.pageSize),this.cursor=0},c.prototype.getData=function(){var d='';for(var a=0;a<this.pages.length;a++)for(var b=0;b<c.pageSize;b++)d+=c.charMap[this.pages[a][b]];return d},c.prototype.writeByte=function(a){this.cursor>=c.pageSize&&this.newPage(),this.pages[this.page][this.cursor++]=a},c.prototype.writeUTFBytes=function(b){for(var c=b.length,a=0;a<c;a++)this.writeByte(b.charCodeAt(a))},c.prototype.writeBytes=function(b,d,e){for(var c=e||b.length,a=d||0;a<c;a++)this.writeByte(b[a])},b.prototype.setDelay=function(a){this.delay=Math.round(a/10)},b.prototype.setFrameRate=function(a){this.delay=Math.round(100/a)},b.prototype.setDispose=function(a){a>=0&&(this.dispose=a)},b.prototype.setRepeat=function(a){this.repeat=a},b.prototype.setTransparent=function(a){this.transparent=a},b.prototype.addFrame=function(a){this.image=a,this.getImagePixels(),this.analyzePixels(),this.firstFrame&&(this.writeLSD(),this.writePalette(),this.repeat>=0&&this.writeNetscapeExt()),this.writeGraphicCtrlExt(),this.writeImageDesc(),this.firstFrame||this.writePalette(),this.writePixels(),this.firstFrame=!1},b.prototype.finish=function(){this.out.writeByte(59)},b.prototype.setQuality=function(a){a<1&&(a=1),this.sample=a},b.prototype.setPreserveColors=function(a){this.preserveColors=a},b.prototype.writeHeader=function(){this.out.writeUTFBytes('GIF89a')},b.prototype.analyzePixels=function(){var h=this.pixels.length,d=h/3;this.indexedPixels=new Uint8Array(d);var a;this.preserveColors?a=new g(this.pixels,this.sample):a=new f(this.pixels,this.sample),a.buildColormap(),this.colorTab=a.getColormap();var b=0;for(var c=0;c<d;c++){var e=a.lookupRGB(this.pixels[b++]&255,this.pixels[b++]&255,this.pixels[b++]&255);this.usedEntry[e]=!0,this.indexedPixels[c]=e}this.pixels=null,this.colorDepth=8,this.palSize=7,this.transparent!==null&&(this.transIndex=this.findClosest(this.transparent))},b.prototype.findClosest=function(e){if(this.colorTab===null)return-1;var k=(e&16711680)>>16,l=(e&65280)>>8,m=e&255,c=0,d=16777216,j=this.colorTab.length;for(var a=0;a<j;){var f=k-(this.colorTab[a++]&255),g=l-(this.colorTab[a++]&255),h=m-(this.colorTab[a]&255),i=f*f+g*g+h*h,b=parseInt(a/3);this.usedEntry[b]&&i<d&&(d=i,c=b),a++}return c},b.prototype.getImagePixels=function(){var a=this.width,g=this.height;this.pixels=new Uint8Array(a*g*3);var b=this.image,c=0;for(var d=0;d<g;d++)for(var e=0;e<a;e++){var f=d*a*4+e*4;this.pixels[c++]=b[f],this.pixels[c++]=b[f+1],this.pixels[c++]=b[f+2]}},b.prototype.writeGraphicCtrlExt=function(){this.out.writeByte(33),this.out.writeByte(249),this.out.writeByte(4);var b,a;this.transparent===null?(b=0,a=0):(b=1,a=2),this.dispose>=0&&(a=dispose&7),a<<=2,this.out.writeByte(0|a|0|b),this.writeShort(this.delay),this.out.writeByte(this.transIndex),this.out.writeByte(0)},b.prototype.writeImageDesc=function(){this.out.writeByte(44),this.writeShort(0),this.writeShort(0),this.writeShort(this.width),this.writeShort(this.height),this.firstFrame?this.out.writeByte(0):this.out.writeByte(128|this.palSize)},b.prototype.writeLSD=function(){this.writeShort(this.width),this.writeShort(this.height),this.out.writeByte(240|this.palSize),this.out.writeByte(0),this.out.writeByte(0)},b.prototype.writeNetscapeExt=function(){this.out.writeByte(33),this.out.writeByte(255),this.out.writeByte(11),this.out.writeUTFBytes('NETSCAPE2.0'),this.out.writeByte(3),this.out.writeByte(1),this.writeShort(this.repeat),this.out.writeByte(0)},b.prototype.writePalette=function(){this.out.writeBytes(this.colorTab);var b=768-this.colorTab.length;for(var a=0;a<b;a++)this.out.writeByte(0)},b.prototype.writeShort=function(a){this.out.writeByte(a&255),this.out.writeByte(a>>8&255)},b.prototype.writePixels=function(){var a=new h(this.width,this.height,this.indexedPixels,this.colorDepth);a.encode(this.out)},b.prototype.stream=function(){return this.out},e.exports=b}),a.define('/LZWEncoder.js',function(e,g,h,i){function f(y,D,C,B){function w(a,b){r[f++]=a,f>=254&&t(b)}function x(b){u(a),k=i+2,j=!0,l(i,b)}function u(b){for(var a=0;a<b;++a)h[a]=-1}function A(z,r){var g,t,d,e,y,w,s;for(q=z,j=!1,n_bits=q,m=p(n_bits),i=1<<z-1,o=i+1,k=i+2,f=0,e=v(),s=0,g=a;g<65536;g*=2)++s;s=8-s,w=a,u(w),l(i,r);a:while((t=v())!=c){if(g=(t<<b)+e,d=t<<s^e,h[d]===g){e=n[d];continue}if(h[d]>=0){y=w-d,d===0&&(y=1);do if((d-=y)<0&&(d+=w),h[d]===g){e=n[d];continue a}while(h[d]>=0)}l(e,r),e=t,k<1<<b?(n[d]=k++,h[d]=g):x(r)}l(e,r),l(o,r)}function z(a){a.writeByte(s),remaining=y*D,curPixel=0,A(s+1,a),a.writeByte(0)}function t(a){f>0&&(a.writeByte(f),a.writeBytes(r,0,f),f=0)}function p(a){return(1<<a)-1}function v(){if(remaining===0)return c;--remaining;var a=C[curPixel++];return a&255}function l(a,c){g&=d[e],e>0?g|=a<<e:g=a,e+=n_bits;while(e>=8)w(g&255,c),g>>=8,e-=8;if((k>m||j)&&(j?(m=p(n_bits=q),j=!1):(++n_bits,n_bits==b?m=1<<b:m=p(n_bits))),a==o){while(e>0)w(g&255,c),g>>=8,e-=8;t(c)}}var s=Math.max(2,B),r=new Uint8Array(256),h=new Int32Array(a),n=new Int32Array(a),g,e=0,f,k=0,m,j=!1,q,i,o;this.encode=z}var c=-1,b=12,a=5003,d=[0,1,3,7,15,31,63,127,255,511,1023,2047,4095,8191,16383,32767,65535];e.exports=f}),a.define('/SimpleQuant.js',function(b,d,e,f){function a(a,b,c){return[a,b,c].join('.')}function c(b){this.pixels=b,this.palette=[],this.paletteIndex={},this.getColormap=function(){return this.palette},this.buildColormap=function(){var h=this.pixels.length/3,b=0;for(var c=0;c<h;c++){var d=this.pixels[b++],e=this.pixels[b++],f=this.pixels[b++],g=a(d,e,f);this.paletteIndex[g]||(this.palette.push(d),this.palette.push(e),this.palette.push(f),this.paletteIndex[g]=this.palette.length/3-1)}},this.lookupRGB=function(b,c,d){return this.paletteIndex[a(b,c,d)]}}b.exports=c}),a.define('/TypedNeuQuant.js',function(A,F,E,D){function C(A,B){function I(){o=[],q=new Int32Array(256),t=new Int32Array(a),y=new Int32Array(a),z=new Int32Array(a>>3);var c,d;for(c=0;c<a;c++)d=(c<<b+8)/a,o[c]=new Float64Array([d,d,d,0]),y[c]=e/a,t[c]=0}function J(){for(var c=0;c<a;c++)o[c][0]>>=b,o[c][1]>>=b,o[c][2]>>=b,o[c][3]=c}function K(b,a,c,e,f){o[a][0]-=b*(o[a][0]-c)/d,o[a][1]-=b*(o[a][1]-e)/d,o[a][2]-=b*(o[a][2]-f)/d}function L(j,e,n,l,k){var h=Math.abs(e-j),i=Math.min(e+j,a),g=e+1,f=e-1,m=1,b,d;while(g<i||f>h)d=z[m++],g<i&&(b=o[g++],b[0]-=d*(b[0]-n)/c,b[1]-=d*(b[1]-l)/c,b[2]-=d*(b[2]-k)/c),f>h&&(b=o[f--],b[0]-=d*(b[0]-n)/c,b[1]-=d*(b[1]-l)/c,b[2]-=d*(b[2]-k)/c)}function C(p,s,q){var h=2147483647,k=h,d=-1,m=d,c,j,e,n,l;for(c=0;c<a;c++)j=o[c],e=Math.abs(j[0]-p)+Math.abs(j[1]-s)+Math.abs(j[2]-q),e<h&&(h=e,d=c),n=e-(t[c]>>i-b),n<k&&(k=n,m=c),l=y[c]>>g,y[c]-=l,t[c]+=l<<f;return y[d]+=x,t[d]-=r,m}function D(){var d,b,e,c,h,g,f=0,i=0;for(d=0;d<a;d++){for(e=o[d],h=d,g=e[1],b=d+1;b<a;b++)c=o[b],c[1]<g&&(h=b,g=c[1]);if(c=o[h],d!=h&&(b=c[0],c[0]=e[0],e[0]=b,b=c[1],c[1]=e[1],e[1]=b,b=c[2],c[2]=e[2],e[2]=b,b=c[3],c[3]=e[3],e[3]=b),g!=f){for(q[f]=i+d>>1,b=f+1;b<g;b++)q[b]=d;f=g,i=d}}for(q[f]=i+n>>1,b=f+1;b<256;b++)q[b]=n}function E(j,i,k){var b,d,c,e=1e3,h=-1,f=q[i],g=f-1;while(f<a||g>=0)f<a&&(d=o[f],c=d[1]-i,c>=e?f=a:(f++,c<0&&(c=-c),b=d[0]-j,b<0&&(b=-b),c+=b,c<e&&(b=d[2]-k,b<0&&(b=-b),c+=b,c<e&&(e=c,h=d[3])))),g>=0&&(d=o[g],c=i-d[1],c>=e?g=-1:(g--,c<0&&(c=-c),b=d[0]-j,b<0&&(b=-b),c+=b,c<e&&(b=d[2]-k,b<0&&(b=-b),c+=b,c<e&&(e=c,h=d[3]))));return h}function F(){var c,f=A.length,D=30+(B-1)/3,y=f/(3*B),q=~~(y/w),n=d,o=u,a=o>>h;for(a<=1&&(a=0),c=0;c<a;c++)z[c]=n*((a*a-c*c)*m/(a*a));var i;f<s?(B=1,i=3):f%l!==0?i=3*l:f%k!==0?i=3*k:f%p!==0?i=3*p:i=3*j;var r,t,x,e,g=0;c=0;while(c<y)if(r=(A[g]&255)<<b,t=(A[g+1]&255)<<b,x=(A[g+2]&255)<<b,e=C(r,t,x),K(n,e,r,t,x),a!==0&&L(a,e,r,t,x),g+=i,g>=f&&(g-=f),c++,q===0&&(q=1),c%q===0)for(n-=n/D,o-=o/v,a=o>>h,a<=1&&(a=0),e=0;e<a;e++)z[e]=n*((a*a-e*e)*m/(a*a))}function G(){I(),F(),J(),D()}function H(){var b=[],g=[];for(var c=0;c<a;c++)g[o[c][3]]=c;var d=0;for(var e=0;e<a;e++){var f=g[e];b[d++]=o[f][0],b[d++]=o[f][1],b[d++]=o[f][2]}return b}var o,q,t,y,z;this.buildColormap=G,this.getColormap=H,this.lookupRGB=E}var w=100,a=256,n=a-1,b=4,i=16,e=1<<i,f=10,B=1<<f,g=10,x=e>>g,r=e<<f-g,z=a>>3,h=6,t=1<<h,u=z*t,v=30,o=10,d=1<<o,q=8,m=1<<q,y=o+q,c=1<<y,l=499,k=491,p=487,j=503,s=3*j;A.exports=C}),a('/gif.worker.coffee')}.call(this,this))
 	};
 	try {
+		var url;
 		if (pskl.utils.UserAgent.isIE11) {
-			window.GifWorkerURL = '/js/lib/gif/gif.ie.worker.js';
+			url = 'js/lib/gif/gif.ie.worker.js';
+			if (window.pskl && window.pskl.appEngineToken_) {
+				url = '../' + url;
+			}
 		} else {
 			var typedArray = [(worker+"").replace(/function \(\)\s?\{/,"").replace(/\}[^}]*$/, "")];
 			var blob = new Blob(typedArray, {type: "application/javascript"}); // pass a useful mime type here
-			window.GifWorkerURL = URL.createObjectURL(blob);
+			url = URL.createObjectURL(blob);
 		}
+		window.GifWorkerURL = url;
 	} catch (e) {
 		console.error("Could not create worker", e.message);
 	}
diff --git a/src/piskel-boot-0.1.0.js b/src/piskel-boot-0.1.0.js
index a07ed840..826badeb 100644
--- a/src/piskel-boot-0.1.0.js
+++ b/src/piskel-boot-0.1.0.js
@@ -1,5 +1,8 @@
 (function () {
 
+  /**
+   * See @Gruntfile.js => after build, @@version is replaced by the build version
+   */
   var version = '@@version';
   var versionHasNotBeenReplaced = version.indexOf('@@') === 0;
   if (versionHasNotBeenReplaced)  {
diff --git a/src/templates/settings/export.html b/src/templates/settings/export.html
index 7a32c810..d26e6bfc 100644
--- a/src/templates/settings/export.html
+++ b/src/templates/settings/export.html
@@ -2,7 +2,7 @@
   <div class="settings-title">
     Export Spritesheet
   </div>
-  <div class="png-export-preview"></div>
+  <div class="png-export-preview  settings-item"></div>
   <div class="settings-item">
     <span class="settings-description">PNG with all frames side by side.</span>
     <button type="button" class="button button-primary png-download-button">Download PNG</button>
@@ -18,19 +18,19 @@
   </div>
   <div class="settings-item">
     <form action="" method="POST" class="gif-export-form">
-      <div style="margin:10px 0;">
+      <div class="settings-item">
         <label>Select resolution:</label>
         <select class="gif-export-select-resolution"></select>
         <script type="text/template" id="gif-export-option-template">
           <option value="{{value}}">{{label}}</option>
         </script>
       </div>
-      <div style="margin:10px 0;">
+      <div class="settings-item">
         <button type="button" class="button button-primary gif-download-button">Download GIF</button>
         <button type="button" class="button button gif-upload-button">Get public URL</button>
       </div>
     </form>
-    <div class="clearfix">
+    <div class="gif-upload">
       <div class="gif-export-preview"></div>
       <div class="gif-upload-status"></div>
     </div>