add a switch to ignore internal image cache

Sources/Private/MainThread/LayerContainers/Utility/CachedImageProvider.swift

@@ -21,7 +21,7 @@ private final class CachedImageProvider: AnimationImageProvider {
   // MARK: Public
 
   public func imageForAsset(asset: ImageAsset) -> CGImage? {
-    if let image = imageCache.object(forKey: asset.id as NSString) {
+    if imageProvider.cacheEligible, let image = imageCache.object(forKey: asset.id as NSString) {
       return image
     }
     if let image = imageProvider.imageForAsset(asset: asset) {

Sources/Public/ImageProvider/AnimationImageProvider.swift

@@ -8,6 +8,8 @@
 import CoreGraphics
 import Foundation
 
+// MARK: - AnimationImageProvider
+
 /// Image provider is a protocol that is used to supply images to `LottieAnimationView`.
 ///
 /// Some animations require a reference to an image. The image provider loads and
@@ -17,5 +19,17 @@ import Foundation
 /// Additionally custom Image Providers can be made to load images from a URL,
 /// or to Cache images.
 public protocol AnimationImageProvider {
+
+  /// Whether or not the resulting image of this image provider can be cached by Lottie. Defaults to true.
+  /// If true, Lottie may internally cache the result of `imageForAsset`
+  var cacheEligible: Bool { get }
+
+  /// The image to display for the given `ImageAsset` defined in the `LottieAnimation` JSON file.
   func imageForAsset(asset: ImageAsset) -> CGImage?
 }
+
+extension AnimationImageProvider {
+  public var cacheEligible: Bool {
+    true
+  }
+}