diff --git a/app/javascript/mastodon/components/media_gallery.js b/app/javascript/mastodon/components/media_gallery.js
index 38b26b1fc..e7f14a7db 100644
--- a/app/javascript/mastodon/components/media_gallery.js
+++ b/app/javascript/mastodon/components/media_gallery.js
@@ -6,7 +6,6 @@ import IconButton from './icon_button';
 import { defineMessages, injectIntl, FormattedMessage } from 'react-intl';
 import { isIOS } from '../is_mobile';
 import classNames from 'classnames';
-import sizeMe from 'react-sizeme';
 
 const messages = defineMessages({
   toggle_visible: { id: 'media_gallery.toggle_visible', defaultMessage: 'Toggle visibility' },
@@ -172,7 +171,6 @@ class Item extends React.PureComponent {
 }
 
 @injectIntl
-@sizeMe({})
 export default class MediaGallery extends React.PureComponent {
 
   static propTypes = {
@@ -209,21 +207,42 @@ export default class MediaGallery extends React.PureComponent {
     this.props.onOpenMedia(this.props.media, index);
   }
 
+  handleRef = (node) => {
+    if (node && this.isStandaloneEligible()) {
+      // offsetWidth triggers a layout, so only calculate when we need to
+      this.setState({
+        width: node.offsetWidth,
+      });
+    }
+  }
+
+  isStandaloneEligible() {
+    const { media, standalone } = this.props;
+    return standalone && media.size === 1 && media.getIn([0, 'meta', 'small', 'aspect']);
+  }
+
   render () {
-    const { media, intl, sensitive, height, standalone, size } = this.props;
+    const { media, intl, sensitive, height } = this.props;
+    const { width, visible } = this.state;
 
     let children;
 
-    const standaloneEligible = standalone && size.width && media.size === 1 && media.getIn([0, 'meta', 'small', 'aspect']);
     const style = {};
 
-    if (standaloneEligible) {
-      style.height = size.width / media.getIn([0, 'meta', 'small', 'aspect']);
+    if (this.isStandaloneEligible()) {
+      if (!visible && width) {
+        // only need to forcibly set the height in "sensitive" mode
+        style.height = width / this.props.media.getIn([0, 'meta', 'small', 'aspect']);
+      } else {
+        // layout automatically, using image's natural aspect ratio
+        style.height = '';
+      }
     } else {
+      // crop the image
       style.height = height;
     }
 
-    if (!this.state.visible) {
+    if (!visible) {
       let warning;
 
       if (sensitive) {
@@ -233,7 +252,7 @@ export default class MediaGallery extends React.PureComponent {
       }
 
       children = (
-        <button className='media-spoiler' onClick={this.handleOpen} style={style}>
+        <button className='media-spoiler' onClick={this.handleOpen} style={style} ref={this.handleRef}>
           <span className='media-spoiler__warning'>{warning}</span>
           <span className='media-spoiler__trigger'><FormattedMessage id='status.sensitive_toggle' defaultMessage='Click to view' /></span>
         </button>
@@ -241,7 +260,7 @@ export default class MediaGallery extends React.PureComponent {
     } else {
       const size = media.take(4).size;
 
-      if (standaloneEligible) {
+      if (this.isStandaloneEligible()) {
         children = <Item standalone onClick={this.handleClick} attachment={media.get(0)} autoPlayGif={this.props.autoPlayGif} />;
       } else {
         children = media.take(4).map((attachment, i) => <Item key={attachment.get('id')} onClick={this.handleClick} attachment={attachment} autoPlayGif={this.props.autoPlayGif} index={i} size={size} />);
@@ -250,8 +269,8 @@ export default class MediaGallery extends React.PureComponent {
 
     return (
       <div className='media-gallery' style={style}>
-        <div className={classNames('spoiler-button', { 'spoiler-button--visible': this.state.visible })}>
-          <IconButton title={intl.formatMessage(messages.toggle_visible)} icon={this.state.visible ? 'eye' : 'eye-slash'} overlay onClick={this.handleOpen} />
+        <div className={classNames('spoiler-button', { 'spoiler-button--visible': visible })}>
+          <IconButton title={intl.formatMessage(messages.toggle_visible)} icon={visible ? 'eye' : 'eye-slash'} overlay onClick={this.handleOpen} />
         </div>
 
         {children}
diff --git a/package.json b/package.json
index 7835a0440..be9b90875 100644
--- a/package.json
+++ b/package.json
@@ -95,7 +95,6 @@
     "react-router-dom": "^4.1.1",
     "react-router-scroll": "ytase/react-router-scroll#build",
     "react-simple-dropdown": "^3.0.0",
-    "react-sizeme": "^2.3.5",
     "react-swipeable-views": "^0.12.3",
     "react-textarea-autosize": "^5.0.7",
     "react-toggle": "^4.0.1",
diff --git a/yarn.lock b/yarn.lock
index 640d06a10..7b8328805 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -982,10 +982,6 @@ base64-js@^1.0.2:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/base64-js/-/base64-js-1.2.1.tgz#a91947da1f4a516ea38e5b4ec0ec3773675e0886"
 
-batch-processor@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/batch-processor/-/batch-processor-1.0.0.tgz#75c95c32b748e0850d10c2b168f6bdbe9891ace8"
-
 batch@0.6.1:
   version "0.6.1"
   resolved "https://registry.yarnpkg.com/batch/-/batch-0.6.1.tgz#dc34314f4e679318093fc760272525f94bf25c16"
@@ -2057,12 +2053,6 @@ electron-to-chromium@^1.2.7, electron-to-chromium@^1.3.14:
   version "1.3.15"
   resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.3.15.tgz#08397934891cbcfaebbd18b82a95b5a481138369"
 
-element-resize-detector@^1.1.12:
-  version "1.1.12"
-  resolved "https://registry.yarnpkg.com/element-resize-detector/-/element-resize-detector-1.1.12.tgz#8b3fd6eedda17f9c00b360a0ea2df9927ae80ba2"
-  dependencies:
-    batch-processor "^1.0.0"
-
 elliptic@^6.0.0:
   version "6.4.0"
   resolved "https://registry.yarnpkg.com/elliptic/-/elliptic-6.4.0.tgz#cac9af8762c85836187003c8dfe193e5e2eae5df"
@@ -5423,14 +5413,6 @@ react-simple-dropdown@^3.0.0:
     classnames "^2.1.2"
     prop-types "^15.5.8"
 
-react-sizeme@^2.3.5:
-  version "2.3.5"
-  resolved "https://registry.yarnpkg.com/react-sizeme/-/react-sizeme-2.3.5.tgz#f14c0a15f9b24d7b8b6f196871b0af19aa01a422"
-  dependencies:
-    element-resize-detector "^1.1.12"
-    invariant "^2.2.2"
-    lodash "^4.17.4"
-
 react-swipeable-views-core@^0.11.1:
   version "0.11.1"
   resolved "https://registry.yarnpkg.com/react-swipeable-views-core/-/react-swipeable-views-core-0.11.1.tgz#61d046799f90725bbf91a0eb3abcab805c774cac"