Create and use IconImageCache. It centralizes and de-dupes logic for getting feed/article images, and it caches the results, which helps performance.

Shared/Activity/ActivityManager.swift

@@ -248,12 +248,11 @@ private extension ActivityManager {
 		attributeSet.title = feed.nameForDisplay
 		attributeSet.keywords = makeKeywords(feed.nameForDisplay)
 		attributeSet.relatedUniqueIdentifier = ActivityManager.identifer(for: feed)
-		if let iconImage = appDelegate.webFeedIconDownloader.icon(for: feed) {
-			attributeSet.thumbnailData = iconImage.image.dataRepresentation()
-		} else if let iconImage = appDelegate.faviconDownloader.faviconAsIcon(for: feed) {
+
+		if let iconImage = IconImageCache.shared.imageForFeed(feed) {
 			attributeSet.thumbnailData = iconImage.image.dataRepresentation()
 		}
-		
+
 		selectingActivity!.contentAttributeSet = attributeSet
 		selectingActivity!.needsSave = true
 		

Shared/Extensions/ArticleUtilities.swift

@@ -96,32 +96,7 @@ extension Article {
 	}
 
 	func iconImage() -> IconImage? {
-		if let authors = authors, authors.count == 1, let author = authors.first {
-			if let image = appDelegate.authorAvatarDownloader.image(for: author) {
-				return image
-			}
-		}
-		
-		if let authors = webFeed?.authors, authors.count == 1, let author = authors.first {
-			if let image = appDelegate.authorAvatarDownloader.image(for: author) {
-				return image
-			}
-		}
-
-		guard let webFeed = webFeed else {
-			return nil
-		}
-		
-		let feedIconImage = appDelegate.webFeedIconDownloader.icon(for: webFeed)
-		if feedIconImage != nil {
-			return feedIconImage
-		}
-		
-		if let faviconImage = appDelegate.faviconDownloader.faviconAsIcon(for: webFeed) {
-			return faviconImage
-		}
-		
-		return FaviconGenerator.favicon(webFeed)
+		return IconImageCache.shared.imageForArticle(self)
 	}
 	
 	func iconImageUrl(webFeed: WebFeed) -> URL? {

Shared/IconImageCache.swift

@@ -0,0 +1,129 @@
+//
+//  IconImageCache.swift
+//  NetNewsWire-iOS
+//
+//  Created by Brent Simmons on 5/2/21.
+//  Copyright © 2021 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import Account
+import Articles
+
+class IconImageCache {
+
+	static var shared = IconImageCache()
+
+	private var smartFeedIconImageCache = [FeedIdentifier: IconImage]()
+	private var webFeedIconImageCache = [FeedIdentifier: IconImage]()
+	private var faviconImageCache = [FeedIdentifier: IconImage]()
+	private var smallIconImageCache = [FeedIdentifier: IconImage]()
+	private var authorIconImageCache = [Author: IconImage]()
+
+	func imageFor(_ feedID: FeedIdentifier) -> IconImage? {
+		if let smartFeed = SmartFeedsController.shared.find(by: feedID) {
+			return imageForFeed(smartFeed)
+		}
+		if let feed = AccountManager.shared.existingFeed(with: feedID) {
+			return imageForFeed(feed)
+		}
+		return nil
+	}
+
+	func imageForFeed(_ feed: Feed) -> IconImage? {
+		guard let feedID = feed.feedID else {
+			return nil
+		}
+		
+		if let smartFeed = feed as? PseudoFeed {
+			return imageForSmartFeed(smartFeed, feedID)
+		}
+		if let webFeed = feed as? WebFeed, let iconImage = imageForWebFeed(webFeed, feedID) {
+			return iconImage
+		}
+		if let smallIconProvider = feed as? SmallIconProvider {
+			return imageForSmallIconProvider(smallIconProvider, feedID)
+		}
+
+		return nil
+	}
+
+	func imageForArticle(_ article: Article) -> IconImage? {
+		if let iconImage = imageForAuthors(article.authors) {
+			return iconImage
+		}
+		guard let feed = article.webFeed else {
+			return nil
+		}
+		return imageForFeed(feed)
+	}
+
+	func emptyCache() {
+		smartFeedIconImageCache = [FeedIdentifier: IconImage]()
+		webFeedIconImageCache = [FeedIdentifier: IconImage]()
+		faviconImageCache = [FeedIdentifier: IconImage]()
+		smallIconImageCache = [FeedIdentifier: IconImage]()
+		authorIconImageCache = [Author: IconImage]()
+	}
+}
+
+private extension IconImageCache {
+	
+	func imageForSmartFeed(_ smartFeed: PseudoFeed, _ feedID: FeedIdentifier) -> IconImage? {
+		if let iconImage = smartFeedIconImageCache[feedID] {
+			return iconImage
+		}
+		if let iconImage = smartFeed.smallIcon {
+			smartFeedIconImageCache[feedID] = iconImage
+			return iconImage
+		}
+		return nil
+	}
+
+	func imageForWebFeed(_ webFeed: WebFeed, _ feedID: FeedIdentifier) -> IconImage? {
+		if let iconImage = webFeedIconImageCache[feedID] {
+			return iconImage
+		}
+		if let iconImage = appDelegate.webFeedIconDownloader.icon(for: webFeed) {
+			webFeedIconImageCache[feedID] = iconImage
+			return iconImage
+		}
+		if let faviconImage = faviconImageCache[feedID] {
+			return faviconImage
+		}
+		if let faviconImage = appDelegate.faviconDownloader.faviconAsIcon(for: webFeed) {
+			faviconImageCache[feedID] = faviconImage
+			return faviconImage
+		}
+		return nil
+	}
+
+	func imageForSmallIconProvider(_ provider: SmallIconProvider, _ feedID: FeedIdentifier) -> IconImage? {
+		if let iconImage = smallIconImageCache[feedID] {
+			return iconImage
+		}
+		if let iconImage = provider.smallIcon {
+			smallIconImageCache[feedID] = iconImage
+			return iconImage
+		}
+		return nil
+	}
+
+	func imageForAuthors(_ authors: Set<Author>?) -> IconImage? {
+		guard let authors = authors, authors.count == 1, let author = authors.first else {
+			return nil
+		}
+		return imageForAuthor(author)
+	}
+
+	func imageForAuthor(_ author: Author) -> IconImage? {
+		if let iconImage = authorIconImageCache[author] {
+			return iconImage
+		}
+		if let iconImage = appDelegate.authorAvatarDownloader.image(for: author) {
+			authorIconImageCache[author] = iconImage
+			return iconImage
+		}
+		return nil
+	}
+}