diff --git a/addons/mail/static/src/js/thread.js b/addons/mail/static/src/js/thread.js
index 8e08ecfa73a..d4bd448d2f8 100644
--- a/addons/mail/static/src/js/thread.js
+++ b/addons/mail/static/src/js/thread.js
@@ -132,6 +132,13 @@ var Thread = Widget.extend({
             } else {
                 msg.display_author = !options.squash_close_messages;
             }
+            if (msg.attachment_ids) {
+                var sortedAttachments = _.partition(msg.attachment_ids, function (att) {
+                    return att.mimetype && att.mimetype.split('/')[0] === 'image';
+                });
+                msg.images = sortedAttachments[0];
+                msg.others = sortedAttachments[1];
+            }
             prev_msg = msg;
         });
 
diff --git a/addons/mail/static/src/less/composer.less b/addons/mail/static/src/less/composer.less
index 1692363446e..0ca031e6f09 100644
--- a/addons/mail/static/src/less/composer.less
+++ b/addons/mail/static/src/less/composer.less
@@ -230,106 +230,164 @@
 
 // Attachment Icons (common for chat thread and chat composer)
 // ------------------------------------------------------------------
-@-webkit-keyframes oe_mail_attach_loading_anim {
-    0% { background: @odoo-brand-optional }
-    50% { background: darken(@odoo-brand-optional, 10%) }
-    100% { background: @odoo-brand-optional }
-}
-@-moz-keyframes oe_mail_attach_loading_anim {
-    0% { background: @odoo-brand-optional }
-    50% { background: darken(@odoo-brand-optional, 10%) }
-    100% { background: @odoo-brand-optional }
-}
-@-o-keyframes oe_mail_attach_loading_anim {
-    0% { background: @odoo-brand-optional }
-    50% { background: darken(@odoo-brand-optional, 10%) }
-    100% { background: @odoo-brand-optional }
-}
-@keyframes oe_mail_attach_loading_anim {
-    0% { background: @odoo-brand-optional }
-    50% { background: darken(@odoo-brand-optional, 10%) }
-    100% { background: @odoo-brand-optional }
+@o-mail-attachment-image-size: 38px;
+@o-mail-attachment-margin: 5px;
+
+.o_attachments_list, .o_attachments_previews {
+    margin: 0 -@o-mail-attachment-margin 0;
+    .o-flex-display();
+    .o-flex-flow(row, wrap);
 }
 
-@o-mail-attachment-image-size: 100px;
 .o_attachment {
     position: relative;
-    vertical-align: top;
-    display: inline-block;
-    text-align: center;
-    width: @o-mail-attachment-image-size;
-    margin: 5px;
-    .o_image_box {
-        position: relative;
-        img {
-            width: @o-mail-attachment-image-size;
-            height: @o-mail-attachment-image-size;
-            image-orientation: from-image; // Only supported in Firefox
-        }
-        .o_image_overlay{
-            display: none;
-        }
-        &:hover .o_image_overlay {
-            display: block;
-            .o-position-absolute(@top: 0, @left: 0, @right:0, @bottom:0);
-            z-index: 20;
-            background: rgba(0, 0, 0, 0.5);
-            overflow: hidden;
-            cursor: pointer;
-            .o_attachment_download {
-                .o-position-absolute(@left: 10px, @bottom:5px);
-            }
-            .o_attachment_play {
-                .o-position-absolute(@top: 50%, @left: 50%);
-                transform: translate(-50%, -50%);
-            }
-            .o_overlay_download {
-                width: 100%;
-                height: 100%;
-            }
-            i {
-                color: #FFFFFF;
-            }
-        }
+    width: 100%;
+    padding: @o-mail-attachment-margin;
+
+    @media (min-width: @screen-sm-min) {
+        width: 50%;
     }
-    .caption {
-        text-overflow: ellipsis;
-        white-space: nowrap;
+    @media (min-width: @screen-md-min) {
+        width: percentage(1/4);
+    }
+
+    .o_attachment_wrap {
         overflow: hidden;
-        padding: 5px;
-        a {
-            color: @odoo-main-text-color;
+        position: relative;
+        border-bottom: 1px solid fade(black, 10%);
+        border-radius: 2px;
+        padding: 4px 6px 0 4px;
+        background-color: fade(black, 5%);
+    }
+
+    &.o_attachment_editable .o_attachment_wrap  {
+        padding-right: 40px;
+    }
+
+    .o_image {
+        .square(@o-mail-attachment-image-size);
+        image-orientation: from-image; // Only supported in Firefox
+        &.o_hover {
+            .o-hover-opacity(@default-opacity: 1, @hover-opacity: 0.7);
         }
     }
+
+    .o_attachment_view {
+        cursor: zoom-in;
+    }
+
+    .caption {
+        .o-text-overflow(block);
+
+        a {
+            .o-hover-text-color(@default-color: @odoo-main-text-color, @hover-color: @headings-color);
+        }
+    }
+
     .o_attachment_progress_bar {
         display: none;
     }
-    .o_attachment_delete {
-        .o-position-absolute(@top: -10px, @right: -8px);
-        color: @odoo-main-text-color;
-        cursor: pointer;
-        opacity: 0;
-        .o-transition(opacity, 0.2s, linear);
+
+    .o_attachment_uploaded, .o_attachment_delete {
+        .o-position-absolute(0,0,0, @left: auto);
+        .o-flex-display();
+        .o-align-items(center);
+        .o-justify-content(center);
+        width: 45px;
     }
+
+    .o_attachment_delete {
+        background: desaturate(@brand-primary, 50%);
+        color: white;
+        cursor: pointer;
+        font-size: 20px;
+        .o-transform(translateX(100%));
+        .o-transition(all, 0.3s);
+
+        &:hover {
+            background: @brand-primary;
+        }
+    }
+
     &.o_attachment_uploading {
         .o_attachment_progress_bar {
-            display: block;
-            .o-position-absolute(@top: 18px, @left: 16px, @right: 16px);
-            height: 17px;
-            line-height: 13px;
-            color: white;
-            border-radius: @border-radius-base;
-            border: solid 1px grey;
-            box-shadow: 0px 1px 10px @odoo-shadow-color;
-            .o-animation(@name: oe_mail_attach_loading_anim, @duration: 1s, @timing-function: linear, @iteration-count: infinite);
+            display: inline-block;
+            margin: 0 0 0 8px;
+            border-radius: 2px;
+            vertical-align: bottom;
+
+            > div {
+                font-size: 11px;
+                padding: 0 7px;
+            }
         }
-        .o_attachment_delete {
+
+        .o_attachment_delete, .o_attachment_uploaded {
             display: none;
         }
     }
+
     &:hover .o_attachment_delete {
-        opacity: 1;
-        .o-transition(opacity, 0.2s, linear);
+        .o-transition(all, 0.1s);
+        .o-transform(translateX(0));
+    }
+}
+
+.o_attachments_previews {
+    > .o_attachment {
+        width: 50%;
+
+        @media (min-width: @screen-sm-min) {
+            width: percentage(1/3);
+        }
+        @media (min-width: @screen-md-min) {
+            width: percentage(1/4);
+        }
+        @media (min-width: @screen-lg-min) {
+            width: percentage(1/6);
+        }
+
+        .o_attachment_wrap {
+            padding: 0;
+            border-radius: 2px;
+            border: 1px solid @gray-lighter-darker;
+        }
+
+        .o_image_box {
+            overflow: hidden;
+            padding-top: 75%;
+
+            .o_attachment_image {
+                .o-position-absolute(0,0,0,0);
+                background-size: cover;
+                background-position: center;
+                .o-transform(scale(1.05));
+                .o-transition(all, 0.3s);
+            }
+
+            &:hover .o_attachment_image {
+                .o-transform(scale(1));
+            }
+        }
+
+        .o_image_overlay {
+            .o-position-absolute(@top: 0, @left: 0, @right:0, @bottom:0);
+            .o-hover-opacity(@default-opacity: 0, @hover-opacity: 1);
+            .o-linear-gradient(180deg, fade(black, 20%), fade(black, 90%));
+            .o-transition(all, 0.3s);
+            padding: 10px;
+
+            .o_attachment_title {
+                .o-position-absolute(@bottom: 7px);
+                width: 80%;
+                .o-text-overflow(inline-block);
+                font-size: @font-size-small;
+            }
+
+            .o_attachment_download {
+                .o-position-absolute(@right: 7px, @bottom:7px);
+            }
+        }
     }
 }
 
diff --git a/addons/mail/static/src/less/thread.less b/addons/mail/static/src/less/thread.less
index 81dee297011..b6bcff71e94 100644
--- a/addons/mail/static/src/less/thread.less
+++ b/addons/mail/static/src/less/thread.less
@@ -177,6 +177,12 @@
                 }
             }
 
+            .o_attachments_list, .o_attachments_previews {
+                &:last-child {
+                    margin-bottom: @grid-gutter-width;
+                }
+            }
+
             .o_thread_tooltip_container {
                 display: inline;
                 position: relative;
diff --git a/addons/mail/static/src/xml/thread.xml b/addons/mail/static/src/xml/thread.xml
index be2a81b4e92..51fa880302c 100644
--- a/addons/mail/static/src/xml/thread.xml
+++ b/addons/mail/static/src/xml/thread.xml
@@ -207,9 +207,18 @@
                     <t t-if="!(message.tracking_value_ids and message.tracking_value_ids.length &gt; 0)">
                         <t t-raw="message.body"/>
                     </t>
-                     <t t-foreach="message.attachment_ids" t-as="attachment">
-                         <t t-call="mail.Attachment"/>
-                     </t>
+                    <t t-if="message.attachment_ids.length > 0">
+                        <div t-if="message.images.length > 0" class="o_attachments_previews">
+                            <t t-foreach="message.images" t-as="attachment">
+                                <t t-call="mail.AttachmentPreview"/>
+                            </t>
+                        </div>
+                        <div t-if="message.others.length > 0" class="o_attachments_list">
+                            <t t-foreach="message.others" t-as="attachment">
+                                <t t-call="mail.Attachment"/>
+                            </t>
+                        </div>
+                    </t>
                 </div>
             </div>
         </div>
@@ -242,7 +251,7 @@
     </t>
 
     <t t-name="mail.ChatComposer.Attachments">
-        <div t-if="attachments.length > 0" class="o_attachments">
+        <div t-if="attachments.length > 0" class="o_attachments o_attachments_list">
             <t t-foreach="attachments" t-as='attachment'>
                 <t t-call="mail.Attachment">
                      <t t-set="editable" t-value="true"/>
@@ -251,68 +260,58 @@
         </div>
     </t>
 
+    <t t-name="mail.AttachmentPreview">
+        <div class="o_attachment" t-att-title="attachment.name">
+            <div class="o_attachment_wrap">
+                <div class="o_image_box">
+                    <div class="o_attachment_image" t-attf-style="background-image:url('/web/image/#{attachment.id}/160x160/?crop=true')"/>
+                    <div t-attf-class="o_image_overlay o_attachment_view"  t-att-data-id="attachment.id">
+                        <span class="o_attachment_title text-white"><t t-esc="attachment.name"/></span>
+                        <a class="o_attachment_download" t-att-href='attachment.url'>
+                            <i t-attf-class="fa fa-download text-white" t-att-title="'Download ' + attachment.name" aria-hidden="true"></i>
+                        </a>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </t>
+
     <t t-name="mail.Attachment">
         <t t-set="type" t-value="attachment.mimetype and attachment.mimetype.split('/').shift()"/>
-        <div t-attf-class="o_attachment #{attachment.upload ? 'o_attachment_uploading' : ''}" t-att-title="attachment.name">
-            <t t-if="type == 'image'">
-                <div class="o_image_box">
-                    <img t-attf-src="/web/image/#{attachment.id}/200x200/?crop=True"/>
-                    <div t-attf-class="o_image_overlay o_attachment_view"  t-att-data-id="attachment.id">
-                        <a class="o_attachment_download" t-att-href='attachment.url' target="_blank">
-                            <i t-attf-class="fa fa-2x fa-arrow-circle-o-down" title="Download this attachment" aria-hidden="true"></i>
-                        </a>
+        <div t-attf-class="o_attachment #{ editable ? 'o_attachment_editable' : '' } #{attachment.upload ? 'o_attachment_uploading' : ''}" t-att-title="attachment.name">
+            <div class="o_attachment_wrap">
+                <t t-set="has_preview" t-value="type == 'image' or type == 'video' or attachment.mimetype == 'application/pdf'"/>
+
+                <div t-attf-class="o_image_box pull-left #{has_preview ? 'o_attachment_view' : ''}" t-att-data-id="attachment.id">
+                    <div t-if="has_preview"
+                         class="o_image o_hover"
+                         t-att-style="type == 'image' ? 'background-image:url(/web/image/' + attachment.id + '/38x38/?crop=true' : '' "
+                         t-att-data-mimetype="attachment.mimetype">
+                    </div>
+                    <a t-elif="!editable" t-att-href='attachment.url' t-att-title="'Download ' + attachment.name">
+                        <span class="o_image o_hover" t-att-data-mimetype="attachment.mimetype"/>
+                    </a>
+                    <span t-else="" class="o_image" t-att-data-mimetype="attachment.mimetype"/>
+                </div>
+
+                <div class="caption">
+                    <span t-if="has_preview or editable" t-attf-class="ml4 #{has_preview? 'o_attachment_view' : ''}" t-att-data-id="attachment.id"><t t-esc='attachment.name'/></span>
+                    <a t-else="" class="ml4" t-att-href="attachment.url" t-att-title="'Download ' + attachment.name"><t t-esc='attachment.name'/></a>
+                </div>
+                <div t-if="editable" class="caption small">
+                    <b t-attf-class="ml4 small text-uppercase #{has_preview? 'o_attachment_view' : ''}" t-att-data-id="attachment.id"><t t-esc="ext"/></b>
+                    <div class="progress o_attachment_progress_bar">
+                        <div class="progress-bar progress-bar-striped active" style="width: 100%">Uploading</div>
                     </div>
                 </div>
-            </t>
-            <t t-elif="type == 'video'">
-                <div class="o_image_box o_image_preview">
-                    <img class="o_image" t-att-data-mimetype="attachment.mimetype"/>
-                    <div t-attf-class="o_image_overlay o_attachment_view"  t-att-data-id="attachment.id">
-                        <a class="o_attachment_play">
-                            <i t-attf-class="fa fa-2x fa-play-circle" title="Play this video" aria-hidden="true"></i>
-                        </a>
-                        <a class="o_attachment_download" t-att-href='attachment.url' target="_blank">
-                            <i t-attf-class="fa fa-2x fa-arrow-circle-o-down" title="Download this attachment" aria-hidden="true"></i>
-                        </a>
-                    </div>
+                <div t-if="!editable" class="caption small">
+                    <b t-if="has_preview" class="ml4 small text-uppercase o_attachment_view" t-att-data-id="attachment.id"><t t-esc="ext"/></b>
+                    <a t-else="" class="ml4 small text-uppercase" t-att-href="attachment.url" t-att-title="'Download ' + attachment.name"><b><t t-esc='ext'/></b></a>
+                    <a class="ml4 o_attachment_download pull-right" t-att-title="'Download ' + attachment.name" t-att-href='attachment.url'><i t-attf-class="fa fa-download"/></a>
                 </div>
-            </t>
-            <t t-elif="attachment.mimetype == 'application/pdf'">
-                <div class="o_image_box">
-                    <div class="o_image_box">
-                        <img src="/web/static/src/img/mimetypes/pdf.png"/>
-                        <div class="o_image_overlay o_attachment_view"  t-att-data-id="attachment.id">
-                            <a class="o_attachment_download" t-att-href='attachment.url' target="_blank">
-                                <i t-attf-class="fa fa-2x fa-arrow-circle-o-down" title="Download this PDF" aria-hidden="true"></i>
-                            </a>
-                        </div>
-                    </div>
-                </div>
-            </t>
-            <t t-else="">
-                <div class="o_image_box">
-                    <img class="o_image" t-att-data-mimetype="attachment.mimetype"/>
-                    <div t-attf-class="o_image_overlay">
-                        <a class="o_overlay_download" t-att-href='attachment.url' target="_blank"/>
-                        <a class="o_attachment_download" t-att-href='attachment.url' target="_blank">
-                            <i t-attf-class="fa fa-2x fa-arrow-circle-o-down" title="Download this attachment" aria-hidden="true"></i>
-                        </a>
-                    </div>
-                </div>
-            </t>
-            <div class="caption">
-                <a t-att-href='attachment.url' target="_blank">
-                    <t t-esc='attachment.name'/>
-                </a>
+                <div t-if="editable" class="o_attachment_uploaded"><i class="text-success fa fa-check"/></div>
+                <div t-if="editable" class="o_attachment_delete" t-att-data-id="attachment.id"><span class="text-white">×</span></div>
             </div>
-            <t t-if="editable">
-                <div class="o_attachment_delete">
-                    <i class='fa fa-times-circle' title="Delete this attachment" t-att-data-id="attachment.id"/>
-                </div>
-                <div class="o_attachment_progress_bar">
-                    Uploading
-                </div>
-            </t>
         </div>
     </t>
 
diff --git a/addons/mail/static/tests/chatter_tests.js b/addons/mail/static/tests/chatter_tests.js
index ddfba7b8af1..56ee5076479 100644
--- a/addons/mail/static/tests/chatter_tests.js
+++ b/addons/mail/static/tests/chatter_tests.js
@@ -684,7 +684,7 @@ QUnit.test('chatter: Attachment viewer', function (assert) {
     });
     assert.strictEqual(form.$('.o_thread_message .o_attachment').length, 4,
         "there should be three attachment on message");
-    assert.strictEqual(form.$('.o_thread_message .o_attachment .caption a').first().attr('href'), '/web/content/1?download=true',
+    assert.strictEqual(form.$('.o_thread_message .o_attachment a').first().attr('href'), '/web/content/1?download=true',
         "image caption should have correct download link");
     // click on first image attachement
     form.$('.o_thread_message .o_attachment .o_image_box .o_image_overlay').first().click();
@@ -699,7 +699,7 @@ QUnit.test('chatter: Attachment viewer', function (assert) {
     // close attachment popup
     $('.o_modal_fullscreen .o_viewer-header .o_close_btn').click();
     // click on pdf attachement
-    form.$('.o_thread_message .o_attachment .o_image_box .o_image_overlay').eq(3).click();
+    form.$('span:contains(Test PDF 1)').click();
     assert.strictEqual($('.o_modal_fullscreen iframe[data-src*="/web/content/4"]').length, 1,
         "Modal popup should open with the pdf preview");
     // close attachment popup