diff --git a/core/js/jquery.avatar.js b/core/js/jquery.avatar.js
index b0d1ca7d88..552657877e 100644
--- a/core/js/jquery.avatar.js
+++ b/core/js/jquery.avatar.js
@@ -77,7 +77,7 @@
 
 		var url = OC.generateUrl(
 			'/avatar/{user}/{size}',
-			{user: user, size: size * window.devicePixelRatio});
+			{user: user, size: Math.ceil(size * window.devicePixelRatio)});
 
 		$.get(url, function(result) {
 			if (typeof(result) === 'object') {
diff --git a/core/js/tests/specs/jquery.avatarSpec.js b/core/js/tests/specs/jquery.avatarSpec.js
new file mode 100644
index 0000000000..f5caae1002
--- /dev/null
+++ b/core/js/tests/specs/jquery.avatarSpec.js
@@ -0,0 +1,240 @@
+/**
+ * Copyright (c) 2015 Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * This file is licensed under the Affero General Public License version 3
+ * or later.
+ *
+ * See the COPYING-README file.
+ *
+ */
+
+describe('jquery.avatar tests', function() {
+	
+	var $div;
+	var devicePixelRatio
+
+	beforeEach(function() {
+		$('#testArea').append($('<div id="avatardiv">'));
+		$div = $('#avatardiv');
+
+		devicePixelRatio = window.devicePixelRatio;
+		window.devicePixelRatio = 1;
+	});
+
+	afterEach(function() {
+		$div.remove();
+
+		window.devicePixelRatio = devicePixelRatio
+	});
+
+	describe('size', function() {
+		it('undefined', function() {
+			$div.avatar('foo');
+
+			expect($div.height()).toEqual(64);
+			expect($div.width()).toEqual(64);
+		});
+
+		it('undefined but div has height', function() {
+			$div.height(9);
+			$div.avatar('foo');
+
+			expect($div.height()).toEqual(9);
+			expect($div.width()).toEqual(9);
+		});
+
+		it('undefined but data size is set', function() {
+			$div.data('size', 10);
+			$div.avatar('foo');
+
+			expect($div.height()).toEqual(10);
+			expect($div.width()).toEqual(10);
+		});
+
+
+		it('defined', function() {
+			$div.avatar('foo', 8);
+
+			expect($div.height()).toEqual(8);
+			expect($div.width()).toEqual(8);
+		});
+	});
+
+	it('undefined user', function() {
+		spyOn($div, 'imageplaceholder');
+
+		$div.avatar();
+		
+		expect($div.imageplaceholder).toHaveBeenCalledWith('x');
+	});
+
+	describe('no avatar', function() {
+		it('show placeholder for existing user', function() {
+			spyOn($div, 'imageplaceholder');
+			$div.avatar('foo');
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'application/json' },
+				JSON.stringify({
+					data: {displayname: 'bar'}
+				})
+			);
+
+			expect($div.imageplaceholder).toHaveBeenCalledWith('foo', 'bar');
+		});
+
+		it('show placeholder for non existing user', function() {
+			spyOn($div, 'imageplaceholder');
+			$div.avatar('foo');
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'application/json' },
+				JSON.stringify({
+					data: {}
+				})
+			);
+
+			expect($div.imageplaceholder).toHaveBeenCalledWith('foo', 'X');
+		});
+
+		it('show no placeholder', function() {
+			spyOn($div, 'imageplaceholder');
+			$div.avatar('foo', undefined, undefined, true);
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'application/json' },
+				JSON.stringify({
+					data: {}
+				})
+			);
+
+			expect($div.imageplaceholder.calls.any()).toEqual(false);
+			expect($div.css('display')).toEqual('none');
+		});
+	});
+
+	describe('url generation', function() {
+		beforeEach(function() {
+			window.devicePixelRatio = 1;
+		});
+
+		it('default', function() {
+			window.devicePixelRatio = 1;
+			$div.avatar('foo', 32);
+
+			expect(fakeServer.requests[0].method).toEqual('GET');
+			expect(fakeServer.requests[0].url).toEqual('http://localhost/index.php/avatar/foo/32');
+		});
+
+		it('high DPI icon', function() {
+			window.devicePixelRatio = 4;
+			$div.avatar('foo', 32);
+
+			expect(fakeServer.requests[0].method).toEqual('GET');
+			expect(fakeServer.requests[0].url).toEqual('http://localhost/index.php/avatar/foo/128');
+		});
+
+		it('high DPI icon round up size', function() {
+			window.devicePixelRatio = 1.9;
+			$div.avatar('foo', 32);
+
+			expect(fakeServer.requests[0].method).toEqual('GET');
+			expect(fakeServer.requests[0].url).toEqual('http://localhost/index.php/avatar/foo/61');
+		});
+	});
+
+	describe('valid avatar', function() {
+		beforeEach(function() {
+			window.devicePixelRatio = 1;
+		});
+
+		it('default (no ie8 fix)', function() {
+			$div.avatar('foo', 32);
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'image/jpeg' },
+				''
+			);
+
+			var img = $div.children('img')[0];
+
+			expect(img.height).toEqual(32);
+			expect(img.width).toEqual(32);
+			expect(img.src).toEqual('http://localhost/index.php/avatar/foo/32');
+		});
+
+		it('default high DPI icon', function() {
+			window.devicePixelRatio = 1.9;
+
+			$div.avatar('foo', 32);
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'image/jpeg' },
+				''
+			);
+
+			var img = $div.children('img')[0];
+
+			expect(img.height).toEqual(32);
+			expect(img.width).toEqual(32);
+			expect(img.src).toEqual('http://localhost/index.php/avatar/foo/61');
+		});
+
+		it('with ie8 fix', function() {
+			sinon.stub(Math, 'random', function() {
+				return 0.5;
+			});
+
+			$div.avatar('foo', 32, true);
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'image/jpeg' },
+				''
+			);
+
+			var img = $div.children('img')[0];
+
+			expect(img.height).toEqual(32);
+			expect(img.width).toEqual(32);
+			expect(img.src).toEqual('http://localhost/index.php/avatar/foo/32#500');
+		});
+
+		it('unhide div', function() {
+			$div.hide();
+
+			$div.avatar('foo', 32);
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'image/jpeg' },
+				''
+			);
+
+			expect($div.css('display')).toEqual('block');
+		});
+
+		it('callback called', function() {
+			var observer = {callback: function() { dump("FOO"); }};
+
+			spyOn(observer, 'callback');
+
+			$div.avatar('foo', 32, undefined, undefined, function() {
+				observer.callback();
+			});
+
+			fakeServer.requests[0].respond(
+				200,
+				{ 'Content-Type': 'image/jpeg' },
+				''
+			);
+
+			expect(observer.callback).toHaveBeenCalled();
+		});
+	});
+});