ChannelThumbnail improvements

- [x] (6332) The IntersectionObserver method of lazy-loading loads cached images visibly late on slower devices. Previously, it was also showing the "broken image" icon briefly, which we mended by placing a dummy transparent image as the initial src.
  - Reverted that ugly transparent image fix.
  - Use the browser's built-in `loading="lazy"` instead. Sorry, Safari.

- [x] Size-optimization did not take "device pixel ratio" into account.
  - When resizing an image through the CDN, we can't just take the dimensions of the tag in pixels directly -- we need to take zooming into account, otherwise the image ends up blurry.
  - Previously, we quickly disabled optimization for the channel avatar in the Channel Page because of this. Now that we know the root-cause, the change was reverted and we now go through the CDN with appropriate sizes. This also improves our Web Vital scores.

- [x] Size-optimization wasn't really implemented for all ChannelThumbnail instances.
  - The CDN-optimized size was hardcoded to the largest instance, so small images like sidebar thumbnails are still loading images that are unnecessarily larger.
  - There's a little-bit of hardcoding of values from CSS here, but I think it's a ok compromise (not something we change often). It also doesn't need to be exact -- the "device pixel ratio" calculate will ensure it's slightly larger than what we need.

- [x] Set `width` and `height` of `<img>` to improve CLS.
  - Addresses Ligthhouse complaints, although technically the shifting was addressed at the `ClaimPreviewTile` level (sub-container dimensions are well defined).
  - Notes: the values don't need to be the final CSS-adjusted sizes. It just needs to be in the right aspect ratio to help the browser pre-allocate space to avoid shifts.

- [x] Add option to disable lazy-load Channel Thumbnails
  - The guidelines mentioned that items that are already in the viewport should not enable `loading="lazy"`.
  - We have a few areas where it doesn't make sense to lazy-load (e.g. thumbnail in Header, channel selector dropdown, publish preview, etc.).

ui/component/channelSelector/view.jsx

@@ -30,7 +30,7 @@ function ChannelListItem(props: ListItemProps) {
 
   return (
     <div className={classnames('channel__list-item', { 'channel__list-item--selected': isSelected })}>
-      <ChannelThumbnail uri={uri} hideStakedIndicator />
+      <ChannelThumbnail uri={uri} hideStakedIndicator xsmall noLazyLoad />
       <ChannelTitle uri={uri} />
       {isSelected && <Icon icon={ICONS.DOWN} />}
     </div>

ui/component/channelThumbnail/view.jsx

@@ -3,11 +3,14 @@ import React from 'react';
 import { parseURI } from 'lbry-redux';
 import classnames from 'classnames';
 import Gerbil from './gerbil.png';
-import Transparent from './transparent_1x1.png';
 import FreezeframeWrapper from 'component/fileThumbnail/FreezeframeWrapper';
 import ChannelStakedIndicator from 'component/channelStakedIndicator';
 import { getThumbnailCdnUrl } from 'util/thumbnail';
-import useLazyLoading from 'effects/use-lazy-loading';
+
+const FONT_PX = 16.0;
+const IMG_XSMALL_REM = 2.1;
+const IMG_SMALL_REM = 3.0;
+const IMG_NORMAL_REM = 10.0;
 
 type Props = {
   thumbnail: ?string,
@@ -16,14 +19,14 @@ type Props = {
   thumbnailPreview: ?string,
   obscure?: boolean,
   small?: boolean,
+  xsmall?: boolean,
   allowGifs?: boolean,
   claim: ?ChannelClaim,
   doResolveUri: (string) => void,
   isResolving: boolean,
   showDelayedMessage?: boolean,
+  noLazyLoad?: boolean,
   hideStakedIndicator?: boolean,
-  xsmall?: boolean,
-  noOptimization?: boolean,
 };
 
 function ChannelThumbnail(props: Props) {
@@ -40,8 +43,8 @@ function ChannelThumbnail(props: Props) {
     doResolveUri,
     isResolving,
     showDelayedMessage = false,
+    noLazyLoad,
     hideStakedIndicator = false,
-    noOptimization,
   } = props;
   const [thumbError, setThumbError] = React.useState(false);
   const shouldResolve = claim === undefined;
@@ -51,6 +54,8 @@ function ChannelThumbnail(props: Props) {
   const isGif = channelThumbnail && channelThumbnail.endsWith('gif');
   const showThumb = (!obscure && !!thumbnail) || thumbnailPreview;
   const thumbnailRef = React.useRef(null);
+  const thumbnailSize = calcRenderedImgWidth(); // currently always 1:1
+
   // Generate a random color class based on the first letter of the channel name
   const { channelName } = parseURI(uri);
   let initializer;
@@ -62,14 +67,26 @@ function ChannelThumbnail(props: Props) {
     colorClassName = `channel-thumbnail__default--4`;
   }
 
+  function calcRenderedImgWidth() {
+    let rem;
+    if (xsmall) {
+      rem = IMG_XSMALL_REM;
+    } else if (small) {
+      rem = IMG_SMALL_REM;
+    } else {
+      rem = IMG_NORMAL_REM;
+    }
+
+    const devicePixelRatio = window.devicePixelRatio || 1.0;
+    return Math.ceil(rem * devicePixelRatio * FONT_PX);
+  }
+
   React.useEffect(() => {
     if (shouldResolve && uri) {
       doResolveUri(uri);
     }
   }, [doResolveUri, shouldResolve, uri]);
 
-  useLazyLoading(thumbnailRef, 0.25, [showThumb, thumbError, channelThumbnail]);
-
   if (isGif && !allowGifs) {
     return (
       <FreezeframeWrapper src={channelThumbnail} className={classnames('channel-thumbnail', className)}>
@@ -81,8 +98,8 @@ function ChannelThumbnail(props: Props) {
   let url = channelThumbnail;
   // @if TARGET='web'
   // Pass image urls through a compression proxy, except for GIFs.
-  if (thumbnail && !noOptimization && !(isGif && allowGifs)) {
+  if (thumbnail && !(isGif && allowGifs)) {
-    url = getThumbnailCdnUrl({ thumbnail });
+    url = getThumbnailCdnUrl({ thumbnail, width: thumbnailSize, height: thumbnailSize, quality: 85 });
   }
   // @endif
 
@@ -100,8 +117,10 @@ function ChannelThumbnail(props: Props) {
           ref={thumbnailRef}
           alt={__('Channel profile picture')}
           className="channel-thumbnail__default"
-          data-src={!thumbError && url ? url : Gerbil}
+          src={!thumbError && url ? url : Gerbil}
-          src={Transparent}
+          width={thumbnailSize}
+          height={thumbnailSize}
+          loading={noLazyLoad ? undefined : 'lazy'}
           onError={() => setThumbError(true)} // if thumb fails (including due to https replace, show gerbil.
         />
       )}
@@ -114,8 +133,10 @@ function ChannelThumbnail(props: Props) {
               ref={thumbnailRef}
               alt={__('Channel profile picture')}
               className="channel-thumbnail__custom"
-              data-src={!thumbError && url ? url : Gerbil}
+              src={!thumbError && url ? url : Gerbil}
-              src={Transparent}
+              width={thumbnailSize}
+              height={thumbnailSize}
+              loading={noLazyLoad ? undefined : 'lazy'}
               onError={() => setThumbError(true)} // if thumb fails (including due to https replace, show gerbil.
             />
           )}

ui/component/claimPreview/view.jsx

@@ -300,7 +300,7 @@ const ClaimPreview = forwardRef<any, {}>((props: Props, ref: any) => {
         >
           {isChannelUri && claim ? (
             <UriIndicator uri={uri} link>
-              <ChannelThumbnail uri={uri} />
+              <ChannelThumbnail uri={uri} small={type === 'inline'} />
             </UriIndicator>
           ) : (
             <>
@@ -404,7 +404,7 @@ const ClaimPreview = forwardRef<any, {}>((props: Props, ref: any) => {
                       <div className="claim-preview__primary-actions">
                         {!isChannelUri && signingChannel && (
                           <div className="claim-preview__channel-staked">
-                            <ChannelThumbnail uri={signingChannel.permanent_url} />
+                            <ChannelThumbnail uri={signingChannel.permanent_url} xsmall />
                           </div>
                         )}
 

ui/component/claimPreviewTile/view.jsx

@@ -226,7 +226,7 @@ function ClaimPreviewTile(props: Props) {
           ) : (
             <React.Fragment>
               <UriIndicator uri={uri} link hideAnonymous>
-                <ChannelThumbnail uri={channelUri} />
+                <ChannelThumbnail uri={channelUri} xsmall />
               </UriIndicator>
 
               <div className="claim-tile__about">

ui/component/comment/view.jsx

@@ -182,9 +182,9 @@ function Comment(props: Props) {
       >
         <div className="comment__thumbnail-wrapper">
           {authorUri ? (
-            <ChannelThumbnail uri={authorUri} obscure={channelIsBlocked} small className="comment__author-thumbnail" />
+            <ChannelThumbnail uri={authorUri} obscure={channelIsBlocked} xsmall className="comment__author-thumbnail" />
           ) : (
-            <ChannelThumbnail small className="comment__author-thumbnail" />
+            <ChannelThumbnail xsmall className="comment__author-thumbnail" />
           )}
         </div>
 

ui/component/commentMenuList/view.jsx

@@ -218,7 +218,7 @@ function CommentMenuList(props: Props) {
 
       {activeChannelClaim && (
         <div className="comment__menu-active">
-          <ChannelThumbnail uri={activeChannelClaim.permanent_url} />
+          <ChannelThumbnail xsmall noLazyLoad uri={activeChannelClaim.permanent_url} />
           <div className="comment__menu-channel">
             {__('Interacting as %channelName%', { channelName: activeChannelClaim.name })}
           </div>

ui/component/commentReactions/view.jsx

@@ -105,7 +105,9 @@ export default function CommentReactions(props: Props) {
           className={classnames('comment__action comment__action--creator-like')}
           onClick={() => react(commentId, REACTION_TYPES.CREATOR_LIKE)}
         >
-          {creatorLiked && <ChannelThumbnail uri={authorUri} hideStakedIndicator className="comment__creator-like" />}
+          {creatorLiked && (
+            <ChannelThumbnail xsmall uri={authorUri} hideStakedIndicator className="comment__creator-like" />
+          )}
         </Button>
       )}
     </>

ui/component/header/view.jsx

@@ -319,7 +319,7 @@ const Header = (props: Props) => {
                       // @endif
                     >
                       {activeChannelUrl ? (
-                        <ChannelThumbnail uri={activeChannelUrl} />
+                        <ChannelThumbnail uri={activeChannelUrl} small noLazyLoad />
                       ) : (
                         <Icon size={18} icon={ICONS.ACCOUNT} aria-hidden />
                       )}

ui/component/sideNavigation/view.jsx

@@ -485,7 +485,7 @@ function SubscriptionListItem({ subscription }: { subscription: Subscription })
         className="navigation-link navigation-link--with-thumbnail"
         activeClass="navigation-link--active"
       >
-        <ChannelThumbnail uri={uri} hideStakedIndicator />
+        <ChannelThumbnail xsmall uri={uri} hideStakedIndicator />
         <span dir="auto" className="button__label">
           {channelName}
         </span>

ui/component/wunderbarSuggestion/view.jsx

@@ -40,7 +40,7 @@ export default function WunderbarSuggestion(props: Props) {
           'wunderbar__suggestion--channel': isChannel,
         })}
       >
-        {isChannel && <ChannelThumbnail uri={uri} />}
+        {isChannel && <ChannelThumbnail small uri={uri} />}
         {!isChannel && (
           <FileThumbnail uri={uri}>
             {/* @if TARGET='app' */}

ui/modal/modalPublishPreview/view.jsx

@@ -199,7 +199,7 @@ const ModalPublishPreview = (props: Props) => {
     const channelClaim = myChannels && myChannels.find((x) => x.name === channel);
     return channel ? (
       <div className="channel-value">
-        {channelClaim && <ChannelThumbnail uri={channelClaim.permanent_url} />}
+        {channelClaim && <ChannelThumbnail xsmall noLazyLoad uri={channelClaim.permanent_url} />}
         {channel}
       </div>
     ) : (

ui/page/channel/view.jsx

@@ -185,13 +185,7 @@ function ChannelPage(props: Props) {
         </div>
         {cover && <img className={classnames('channel-cover__custom')} src={cover} />}
         <div className="channel__primary-info">
-          <ChannelThumbnail
+          <ChannelThumbnail className="channel__thumbnail--channel-page" uri={uri} allowGifs hideStakedIndicator />
-            className="channel__thumbnail--channel-page"
-            uri={uri}
-            allowGifs
-            hideStakedIndicator
-            noOptimization
-          />
           <h1 className="channel__title">
             {title || '@' + channelName}
             <ChannelStakedIndicator uri={uri} large />