It is time.

ui/accessibility/extensions/alt/hide-images.css

-/* Copyright (c) 2014 The Chromium Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file. */
-
-body[show-alt] img {
-    /* add some fake content to hang the ::before element off */
-    content: "" !important;
-    background-image: url('data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7')
-
-    /* display non-floated and remove any background color */
-    float: none !important;
-    background-color: inherit !important;
-
-    /* set height to contain the text content */
-    height: 100% !important;
-}
-
-body[show-alt] img:not([alt]):not([aria-hidden=true]):not([role=presentation]):before {
-    content: url('chrome-extension://__MSG_@@extension_id__/images/speech-missing-alt-16.png') " " attr(_repaired) !important;
-    box-shadow: inset 0 -4px 0 rgba(230, 124, 115, 1) !important;
-}
-
-body[show-alt] img:not([aria-hidden=true]):not([role=presentation]):not([alt='']):before {
-    content: url('chrome-extension://__MSG_@@extension_id__/images/speech-16.png') " " attr(alt) !important;
-    box-shadow: inset 0 -4px 0 rgba(139, 195, 74, 1) !important;
-    display: table;
-    clear: both;
-}
-
-@-webkit-keyframes slideDown {
-    from {
-      -webkit-transform: translateY(-150%);
-    }
-    to {
-      -webkit-transform: translateY(0px);
-    }
-}
-
-@-webkit-keyframes slideUp {
-    from {
-      -webkit-transform: translateY(0%);
-    }
-    to {
-      -webkit-transform: translateY(-150%);
-    }
-}
-
-body[show-alt] .show-alt-infobar {
-    -webkit-animation-name: slideDown;
-    -webkit-animation-duration: 0.5s;
-    -webkit-animation-delay: 0.5s;
-    -webkit-animation-iteration-count: 1;
-    -webkit-animation-timing-function: ease;
-    -webkit-animation-direction: forwards;
-    -webkit-transform: translateY(0%);
-}
-
-body:not([show-alt]) .show-alt-infobar {
-    -webkit-animation-name: slideUp;
-    -webkit-animation-duration: 0.5s;
-    -webkit-animation-delay: 0.5s;
-    -webkit-animation-iteration-count: 1;
-    -webkit-animation-timing-function: ease;
-    -webkit-animation-direction: forwards;
-    -webkit-transform: translateY(-150%);
-}
-
-.show-alt-infobar {
-    top: 0;
-    left: 0;
-    right: 0;
-    z-index: 100000001;  /* :( */
-    position: fixed !important;
-    background: #fde073 !important;
-    text-align: center !important;
-    line-height: 2.0;
-    overflow: hidden;
-    box-shadow: 0 0 5px black;
-    box-shadow:         0 0 5px black;
-    font-family: Arial, sans-serif !important;
-    font-size: 12pt !important;
-    -webkit-animation-fill-mode: backwards;
-}
-
-.show-alt-infobar .content {
-    display: inline-block !important;
-}
-
-.show-alt-infobar span {
-    margin: 5px;
-}
-
-.show-alt-infobar button.link-button {
-    -webkit-appearance: none !important;
-    font: inherit !important;
-    background: inherit !important;
-    border: none !important;
-    color: #1155CC !important;
-    cursor: pointer !important;
-    display: inline !important;
-    margin: 0 !important;
-    padding: 0 !important;
-    text-decoration: none !important;
-    box-shadow: none !important;
-    text-transform: none !important;
-    padding: none !important;
-}
-
-.show-alt-infobar button.link-button:hover,
-.show-alt-infobar button.link-button:focus {
-    color: #1155CC;
-    text-decoration: underline;
-    outline: none;
-}
-
-.show-alt-infobar .controls {
-    float: right !important;
-    display: inline-block !important;
-    padding-right: 5px !important;
-}
-
-.show-alt-infobar .close-button-gray:hover,
-.show-alt-infobar .close-button-gray:focus {
-    background-position: -143px -96px !important;
-    outline: none;
-}
-
-.show-alt-infobar .close-button-gray {
-    -webkit-appearance: none !important;
-    font: inherit !important;
-    background: inherit !important;
-    border: none !important;
-    cursor: pointer !important;
-    margin: 0 !important;
-    padding: 0 !important;
-    text-decoration: none !important;
-    box-shadow: none !important;
-    text-transform: none !important;
-    padding: none !important;
-    width: 13px !important;
-    height: 13px !important;
-    background-position: -175px -96px !important;
-    background-image: url('chrome-extension://__MSG_@@extension_id__/images/statusbarButtonGlyphs.png') !important;
-    background-size: 320px 144px !important;
-    display: inline-block !important;
-}