Improve fallback of Group Avatars not loading

app/soapbox/components/group-card.tsx

@@ -1,6 +1,6 @@
 import React from 'react';
-import { defineMessages, useIntl } from 'react-intl';
 
+import GroupHeaderImage from 'soapbox/features/group/components/group-header-image';
 import GroupMemberCount from 'soapbox/features/group/components/group-member-count';
 import GroupPrivacy from 'soapbox/features/group/components/group-privacy';
 import GroupRelationship from 'soapbox/features/group/components/group-relationship';
@@ -10,17 +10,11 @@ import { HStack, Stack, Text } from './ui';
 
 import type { Group as GroupEntity } from 'soapbox/types/entities';
 
-const messages = defineMessages({
-  groupHeader: { id: 'group.header.alt', defaultMessage: 'Group header' },
-});
-
 interface IGroupCard {
   group: GroupEntity
 }
 
 const GroupCard: React.FC<IGroupCard> = ({ group }) => {
-  const intl = useIntl();
-
   return (
     <Stack
       className='relative h-[240px] rounded-lg border border-solid border-gray-300 bg-white dark:border-primary-800 dark:bg-primary-900'
@@ -28,12 +22,10 @@ const GroupCard: React.FC<IGroupCard> = ({ group }) => {
     >
       {/* Group Cover Image */}
       <Stack grow className='relative basis-1/2 rounded-t-lg bg-primary-100 dark:bg-gray-800'>
-        {group.header && (
-          <img
-            className='absolute inset-0 h-full w-full rounded-t-lg object-cover'
-            src={group.header} alt={intl.formatMessage(messages.groupHeader)}
-          />
-        )}
+        <GroupHeaderImage
+          group={group}
+          className='absolute inset-0 h-full w-full rounded-t-lg object-cover'
+        />
       </Stack>
 
       {/* Group Avatar */}

app/soapbox/components/still-image.tsx

@@ -3,7 +3,7 @@ import React, { useRef } from 'react';
 
 import { useSettings } from 'soapbox/hooks';
 
-interface IStillImage {
+export interface IStillImage {
   /** Image alt text. */
   alt?: string
   /** Extra class names for the outer <div> container. */

app/soapbox/components/ui/avatar/avatar.tsx

@@ -1,34 +1,54 @@
 import clsx from 'clsx';
-import React from 'react';
+import React, { useState } from 'react';
 
-import StillImage from 'soapbox/components/still-image';
+import StillImage, { IStillImage } from 'soapbox/components/still-image';
+
+import Icon from '../icon/icon';
 
 const AVATAR_SIZE = 42;
 
-interface IAvatar {
-  /** URL to the avatar image. */
-  src: string
+interface IAvatar extends Pick<IStillImage, 'src' | 'onError' | 'className'> {
   /** Width and height of the avatar in pixels. */
   size?: number
-  /** Extra class names for the div surrounding the avatar image. */
-  className?: string
 }
 
 /** Round profile avatar for accounts. */
 const Avatar = (props: IAvatar) => {
   const { src, size = AVATAR_SIZE, className } = props;
 
+  const [isAvatarMissing, setIsAvatarMissing] = useState<boolean>(false);
+
+  const handleLoadFailure = () => setIsAvatarMissing(true);
+
   const style: React.CSSProperties = React.useMemo(() => ({
     width: size,
     height: size,
   }), [size]);
 
+  if (isAvatarMissing) {
+    return (
+      <div
+        style={{
+          width: size,
+          height: size,
+        }}
+        className={clsx('flex items-center justify-center rounded-full bg-gray-200 dark:bg-gray-900', className)}
+      >
+        <Icon
+          src={require('@tabler/icons/photo-off.svg')}
+          className='h-4 w-4 text-gray-500 dark:text-gray-700'
+        />
+      </div>
+    );
+  }
+
   return (
     <StillImage
       className={clsx('rounded-full', className)}
       style={style}
       src={src}
       alt='Avatar'
+      onError={handleLoadFailure}
     />
   );
 };

app/soapbox/features/group/components/group-header-image.tsx

@@ -0,0 +1,50 @@
+import clsx from 'clsx';
+import React, { useState } from 'react';
+import { defineMessages, useIntl } from 'react-intl';
+
+import { Icon } from 'soapbox/components/ui';
+
+import type { Group } from 'soapbox/schemas';
+
+const messages = defineMessages({
+  header: { id: 'group.header.alt', defaultMessage: 'Group header' },
+});
+
+interface IGroupHeaderImage {
+  group?: Group | false | null
+  className?: string
+}
+
+const GroupHeaderImage: React.FC<IGroupHeaderImage> = ({ className, group }) => {
+  const intl = useIntl();
+
+  const [isHeaderMissing, setIsHeaderMissing] = useState<boolean>(false);
+
+  if (!group || !group.header) {
+    return null;
+  }
+
+  if (isHeaderMissing) {
+    return (
+      <div
+        className={clsx(className, 'flex items-center justify-center bg-gray-200 dark:bg-gray-800/30')}
+      >
+        <Icon
+          src={require('@tabler/icons/photo-off.svg')}
+          className='h-6 w-6 text-gray-500 dark:text-gray-700'
+        />
+      </div>
+    );
+  }
+
+  return (
+    <img
+      className={className}
+      src={group.header}
+      alt={intl.formatMessage(messages.header)}
+      onError={() => setIsHeaderMissing(true)}
+    />
+  );
+};
+
+export default GroupHeaderImage;

app/soapbox/features/groups/components/discover/group-grid-item.tsx

@@ -4,6 +4,7 @@ import { Link } from 'react-router-dom';
 import GroupAvatar from 'soapbox/components/groups/group-avatar';
 import { HStack, Stack, Text } from 'soapbox/components/ui';
 import GroupActionButton from 'soapbox/features/group/components/group-action-button';
+import GroupHeaderImage from 'soapbox/features/group/components/group-header-image';
 import GroupMemberCount from 'soapbox/features/group/components/group-member-count';
 import GroupPrivacy from 'soapbox/features/group/components/group-privacy';
 
@@ -31,13 +32,10 @@ const GroupGridItem = forwardRef((props: IGroup, ref: React.ForwardedRef<HTMLDiv
           ref={ref}
           style={{ minHeight: 180 }}
         >
-          {group.header && (
-            <img
-              src={group.header}
-              alt='Group cover'
-              className='absolute inset-0 object-cover'
-            />
-          )}
+          <GroupHeaderImage
+            group={group}
+            className='absolute inset-0 object-cover'
+          />
 
           <div
             className='absolute inset-x-0 bottom-0 flex justify-center rounded-b-lg bg-gradient-to-t from-gray-900 to-transparent pb-8 pt-12 transition-opacity duration-500'