diff --git a/components/emojijs/demo/emoji.css b/components/emojijs/demo/emoji.css
index 4a334edaf..25b57c884 100644
--- a/components/emojijs/demo/emoji.css
+++ b/components/emojijs/demo/emoji.css
@@ -44,3 +44,20 @@ img.emoji {
 	width: 1em;
 	height: 1em;
 }
+
+img.emoji.small {
+	width: 1.25em;
+	height: 1.25em;
+}
+img.emoji.medium {
+	width: 1.5em;
+	height: 1.5em;
+}
+img.emoji.large {
+	width: 1.75em;
+	height: 1.75em;
+}
+img.emoji.jumbo {
+	width: 2em;
+	height: 2em;
+}
diff --git a/js/emoji_util.js b/js/emoji_util.js
index 50702bc25..f4659732e 100644
--- a/js/emoji_util.js
+++ b/js/emoji_util.js
@@ -16,9 +16,83 @@
         this.img_sets.apple.path = '/images/emoji/apple/';
         this.replace_mode = 'img';
     };
+
+    EmojiConvertor.prototype.getCountOfAllMatches = function(str, regex) {
+        var match = regex.exec(str);
+        var count = 0;
+
+        while (match) {
+            count += 1;
+            match = regex.exec(str);
+        }
+
+        return count;
+    };
+
+    EmojiConvertor.prototype.hasNormalCharacters = function(str) {
+        var self = this;
+        var noEmoji = str.replace(self.rx_unified, '').trim();
+        return noEmoji.length > 0;
+    };
+
+    EmojiConvertor.prototype.getSizeClass = function(str) {
+        var self = this;
+
+        if (self.hasNormalCharacters(str)) {
+            return '';
+        }
+
+        var emojiCount = self.getCountOfAllMatches(str, self.rx_unified);
+        if (emojiCount > 8) {
+            return '';
+        }
+        else if (emojiCount > 6) {
+            return 'small';
+        }
+        else if (emojiCount > 4) {
+            return 'medium';
+        }
+        else if (emojiCount > 2) {
+            return 'large';
+        }
+        else {
+            return 'jumbo';
+        }
+    };
+
+    // A stripped-down version of the original: https://github.com/WhisperSystems/Signal-Desktop/blob/aed573562018462fbacd8f2f715e9daeddcde0dd/components/emojijs/lib/emoji.js#L323-L396
+    // One primary change - we inject the second parameter as an additional class
+    EmojiConvertor.prototype.replacement = function(idx, sizeClass, actual, wrapper, variation) {
+        var self = this;
+        var img_set = self.img_set;
+
+        var extra = '';
+        var variation_idx = 0;
+        if (typeof variation === 'object') {
+            extra = self.replacement(variation.idx, null, variation.actual, variation.wrapper);
+            variation_idx = idx + '-' + variation.idx;
+        }
+
+        var img = self.data[idx][7] || self.img_sets[img_set].path + idx + '.png' + self.img_suffix;
+        var title = self.include_title ? ' title="' + (actual || self.data[idx][3][0]) + '"' : '';
+
+        if (variation_idx && self.variations_data[variation_idx] && self.variations_data[variation_idx][2] && !self.data[idx][7]) {
+            if (self.variations_data[variation_idx][2] & self.img_sets[self.img_set].mask) {
+                img = self.img_sets[self.img_set].path + variation_idx + '.png';
+                extra = '';
+            }
+        }
+
+        return '<img src="' + img + '" class="emoji' + (sizeClass ?  ' ' + sizeClass : '') + '"' + title + '/>';
+    };
+
+    // Modeled after the original: https://github.com/WhisperSystems/Signal-Desktop/blob/aed573562018462fbacd8f2f715e9daeddcde0dd/components/emojijs/lib/emoji.js#L265-L286
     EmojiConvertor.prototype.replace_unified = function(str) {
         var self = this;
         self.init_unified();
+
+        var sizeClass = self.getSizeClass(str);
+
         return str.replace(self.rx_unified, function(m, p1, p2) {
             var val = self.map.unified[p1];
             if (!val) { return m; }
@@ -29,14 +103,14 @@
             if (p2 == '\uD83C\uDFFE') { idx = '1f3fe'; }
             if (p2 == '\uD83C\uDFFF') { idx = '1f3ff'; }
             if (idx) {
-                return self.replacement(val, null, null, {
+                return self.replacement(val, sizeClass, null, null, {
                     idx : idx,
                     actual  : p2,
                     wrapper : ':'
                 });
             }
             // wrap names in :'s
-            return self.replacement(val, ':' + self.data[val][3][0] + ':');
+            return self.replacement(val, sizeClass, ':' + self.data[val][3][0] + ':');
         });
     };
     window.emoji = new EmojiConvertor();
@@ -46,6 +120,7 @@
         if (!$el || !$el.length) {
             return;
         }
+
         $el.html(emoji.replace_unified($el.html()));
     };
 
diff --git a/stylesheets/manifest.css b/stylesheets/manifest.css
index bfd594963..93abea79f 100644
--- a/stylesheets/manifest.css
+++ b/stylesheets/manifest.css
@@ -704,6 +704,22 @@ img.emoji {
   width: 1em;
   height: 1em; }
 
+img.emoji.small {
+  width: 1.25em;
+  height: 1.25em; }
+
+img.emoji.medium {
+  width: 1.5em;
+  height: 1.5em; }
+
+img.emoji.large {
+  width: 1.75em;
+  height: 1.75em; }
+
+img.emoji.jumbo {
+  width: 2em;
+  height: 2em; }
+
 .settings.modal {
   padding: 50px; }
   .settings.modal .content {
diff --git a/test/emoji_util_test.js b/test/emoji_util_test.js
new file mode 100644
index 000000000..e306f4c00
--- /dev/null
+++ b/test/emoji_util_test.js
@@ -0,0 +1,102 @@
+'use strict';
+
+describe('EmojiUtil', function() {
+    describe('getCountOfAllMatches', function() {
+        it('returns zero for string with no matches', function() {
+            var r = /s/g;
+            var str = 'no match';
+            var actual = emoji.getCountOfAllMatches(str, r);
+            assert.equal(actual, 0);
+        });
+        it('returns 1 for one match', function() {
+            var r = /s/g;
+            var str = 'just one match';
+            var actual = emoji.getCountOfAllMatches(str, r);
+            assert.equal(actual, 1);
+        });
+        it('returns 2 for two matches', function() {
+            var r = /s/g;
+            var str = 's + s';
+            var actual = emoji.getCountOfAllMatches(str, r);
+            assert.equal(actual, 2);
+        });
+    });
+
+    describe('hasNormalCharacters', function() {
+        it('returns true for all normal text', function() {
+            var str = 'normal';
+            var actual = emoji.hasNormalCharacters(str);
+            assert.equal(actual, true);
+        });
+        it('returns false for all emoji text', function() {
+            var str = '🔥🔥🔥🔥';
+            var actual = emoji.hasNormalCharacters(str);
+            assert.equal(actual, false);
+        });
+        it('returns false for emojis mixed with spaces', function() {
+            var str = '🔥 🔥 🔥 🔥';
+            var actual = emoji.hasNormalCharacters(str);
+            assert.equal(actual, false);
+        });
+        it('returns true for emojis and text', function() {
+            var str = '🔥 normal 🔥 🔥 🔥';
+            var actual = emoji.hasNormalCharacters(str);
+            assert.equal(actual, true);
+        });
+    });
+
+    describe('getSizeClass', function() {
+        it('returns nothing for non-emoji text', function() {
+            assert.equal(emoji.getSizeClass('normal text'), '');
+        });
+        it('returns nothing for emojis mixed with text', function() {
+            assert.equal(emoji.getSizeClass('🔥 normal 🔥'), '');
+        });
+        it('returns nothing for more than 8 emojis', function() {
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥🔥 🔥🔥 🔥🔥 🔥'), '');
+        });
+        it('returns "small" for 7-8 emojis', function() {
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥🔥 🔥🔥 🔥🔥'), 'small');
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥🔥 🔥🔥 🔥'), 'small');
+        });
+        it('returns "medium" for 5-6 emojis', function() {
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥🔥 🔥🔥'), 'medium');
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥🔥 🔥'), 'medium');
+        });
+        it('returns "large" for 3-4 emojis', function() {
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥🔥'), 'large');
+            assert.equal(emoji.getSizeClass('🔥🔥 🔥'), 'large');
+        });
+        it('returns "jumbo" for 1-2 emojis', function() {
+            assert.equal(emoji.getSizeClass('🔥🔥'), 'jumbo');
+            assert.equal(emoji.getSizeClass('🔥'), 'jumbo');
+        });
+    });
+
+    describe('replacement', function() {
+        it('returns an <img> tag', function() {
+            var actual = emoji.replacement('1f525');
+            assert.equal(actual, '<img src="/images/emoji/apple/1f525.png" class="emoji" title="fire"/>');
+        });
+        it('returns an <img> tag with provided sizeClass', function() {
+            var actual = emoji.replacement('1f525', 'large');
+            assert.equal(actual, '<img src="/images/emoji/apple/1f525.png" class="emoji large" title="fire"/>');
+        });
+    });
+
+    describe('replace_unified', function() {
+        it('returns images for every emoji', function() {
+            var actual = emoji.replace_unified('🏠 🔥');
+            var expected = '<img src="/images/emoji/apple/1f3e0.png" class="emoji jumbo" title=":house:"/>'
+                + ' <img src="/images/emoji/apple/1f525.png" class="emoji jumbo" title=":fire:"/>';
+
+            assert.equal(expected, actual);
+        });
+        it('properly hyphenates a variation', function() {
+            var actual = emoji.replace_unified('💪🏿'); // muscle with dark skin tone modifier
+            var expected = '<img src="/images/emoji/apple/1f4aa-1f3ff.png" class="emoji jumbo" title="muscle"/>';
+
+            assert.equal(expected, actual);
+        });
+    });
+});
diff --git a/test/index.html b/test/index.html
index 4f72299d2..706eb60fc 100644
--- a/test/index.html
+++ b/test/index.html
@@ -576,6 +576,7 @@
   <script type="text/javascript" src="models/messages_test.js"></script>
   <script type="text/javascript" src="storage_test.js"></script>
   <script type="text/javascript" src="keychange_listener_test.js"></script>
+  <script type="text/javascript" src="emoji_util_test.js"></script>
 
   <script type="text/javascript" src="fixtures.js"></script>
   <script type="text/javascript" src="fixtures_test.js"></script>