diff --git a/Sources/Generator/Processing/ImageGenerator.swift b/Sources/Generator/Processing/ImageGenerator.swift
index ec67b91..962d1eb 100644
--- a/Sources/Generator/Processing/ImageGenerator.swift
+++ b/Sources/Generator/Processing/ImageGenerator.swift
@@ -266,8 +266,9 @@ final class ImageGenerator {
         let all = generatedImages
             .filter { imageOptimSupportedFileExtensions.contains($0.lastComponentAfter(".")) }
             .map { output.appendingPathComponent($0).path }
-        for i in stride(from: 0, to: all.count, by: imageOptimizationBatchSize) {
-            let endIndex = min(i+imageOptimizationBatchSize, all.count)
+        numberOfImagesToOptimize = all.count
+        for i in stride(from: 0, to: numberOfImagesToOptimize, by: imageOptimizationBatchSize) {
+            let endIndex = min(i+imageOptimizationBatchSize, numberOfImagesToOptimize)
             let batch = all[i..<endIndex]
             if optimizeImageBatch(batch) {
                 optimizedImages.formUnion(batch)