diff --git a/WordPress/src/main/java/org/wordpress/android/ui/reader/utils/ImageSizeMap.java b/WordPress/src/main/java/org/wordpress/android/ui/reader/utils/ImageSizeMap.java
deleted file mode 100644
index b5c7812d4004..000000000000
--- a/WordPress/src/main/java/org/wordpress/android/ui/reader/utils/ImageSizeMap.java
+++ /dev/null
@@ -1,100 +0,0 @@
-package org.wordpress.android.ui.reader.utils;
-
-import android.net.Uri;
-import android.text.TextUtils;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-
-import org.json.JSONException;
-import org.json.JSONObject;
-import org.wordpress.android.util.AppLog;
-import org.wordpress.android.util.JSONUtils;
-import org.wordpress.android.util.UrlUtils;
-
-import java.util.HashMap;
-import java.util.Iterator;
-
-/**
- * hash map of sizes of attachments in a reader post - created from the json "attachments" section
- * of the post endpoints
- */
-public class ImageSizeMap extends HashMap<String, ImageSizeMap.ImageSize> {
-    private static final String EMPTY_JSON = "{}";
-
-    public ImageSizeMap(@NonNull String postContent, String jsonString) {
-        if (TextUtils.isEmpty(jsonString) || jsonString.equals(EMPTY_JSON)) {
-            return;
-        }
-
-        try {
-            JSONObject json = new JSONObject(jsonString);
-            Iterator<String> it = json.keys();
-            if (!it.hasNext()) {
-                return;
-            }
-
-            while (it.hasNext()) {
-                JSONObject jsonAttach = json.optJSONObject(it.next());
-                if (jsonAttach != null && JSONUtils.getString(jsonAttach, "mime_type").startsWith("image")) {
-                    String normUrl =
-                            UrlUtils.normalizeUrl(UrlUtils.removeQuery(JSONUtils.getString(jsonAttach, "URL")));
-
-                    // make sure this image actually appears in the post content - it's possible for
-                    // an image to be in the attachments but not in the post itself
-                    String path = Uri.parse(normUrl).getPath();
-                    if (postContent.contains(path)) {
-                        int width = jsonAttach.optInt("width");
-                        int height = jsonAttach.optInt("height");
-
-                        // chech if data-orig-size is present and use it
-                        String originalSize = jsonAttach.optString("data-orig-size", null);
-                        if (originalSize != null) {
-                            String[] sizes = originalSize.split(",");
-                            if (sizes != null && sizes.length == 2) {
-                                width = Integer.parseInt(sizes[0]);
-                                height = Integer.parseInt(sizes[1]);
-                            }
-                        }
-
-                        this.put(normUrl, new ImageSize(width, height));
-                    }
-                }
-            }
-        } catch (JSONException e) {
-            AppLog.e(AppLog.T.READER, e);
-        }
-    }
-
-    @Nullable
-    public ImageSize getImageSize(final String imageUrl) {
-        if (imageUrl == null) {
-            return null;
-        } else {
-            return super.get(UrlUtils.normalizeUrl(UrlUtils.removeQuery(imageUrl)));
-        }
-    }
-
-    public String getLargestImageUrl(int minImageWidth) {
-        String currentImageUrl = null;
-        int currentMaxWidth = minImageWidth;
-        for (Entry<String, ImageSize> attach : this.entrySet()) {
-            if (attach.getValue().width > currentMaxWidth) {
-                currentImageUrl = attach.getKey();
-                currentMaxWidth = attach.getValue().width;
-            }
-        }
-
-        return currentImageUrl;
-    }
-
-    public static class ImageSize {
-        public final int width;
-        public final int height;
-
-        public ImageSize(int width, int height) {
-            this.width = width;
-            this.height = height;
-        }
-    }
-}
diff --git a/WordPress/src/main/java/org/wordpress/android/ui/reader/utils/ImageSizeMap.kt b/WordPress/src/main/java/org/wordpress/android/ui/reader/utils/ImageSizeMap.kt
new file mode 100644
index 000000000000..54f27858b312
--- /dev/null
+++ b/WordPress/src/main/java/org/wordpress/android/ui/reader/utils/ImageSizeMap.kt
@@ -0,0 +1,82 @@
+package org.wordpress.android.ui.reader.utils
+
+import org.json.JSONException
+import org.json.JSONObject
+import org.wordpress.android.util.AppLog
+import org.wordpress.android.util.JSONUtils
+import org.wordpress.android.util.UrlUtils
+import androidx.core.net.toUri
+
+/**
+ * hash map of sizes of attachments in a reader post - created from the json "attachments" section
+ * of the post endpoints
+ */
+class ImageSizeMap(private val postContent: String, private val jsonString: String) :
+    HashMap<String, ImageSizeMap.ImageSize>() {
+    init {
+        if (jsonString.isNotEmpty() && jsonString != EMPTY_JSON) {
+            parseJson()
+        }
+    }
+
+    @Suppress("NestedBlockDepth")
+    private fun parseJson() {
+        try {
+            val json = JSONObject(jsonString)
+            val keys = json.keys()
+            while (keys.hasNext()) {
+                json.optJSONObject(keys.next())?.let { jsonAttach ->
+                    val mimeType = JSONUtils.getString(jsonAttach, "mime_type")
+                    if (mimeType.startsWith("image")) {
+                        parseJsonImage(jsonAttach)
+                    }
+                }
+            }
+        } catch (e: JSONException) {
+            AppLog.e(AppLog.T.READER, e)
+        }
+    }
+
+    private fun parseJsonImage(jsonImage: JSONObject) {
+        val imageUrl = JSONUtils.getString(
+            jsonImage,
+            "URL"
+        )
+        val key = getKeyFromImageUrl(imageUrl)
+
+        // make sure this image actually appears in the post content - it's possible for
+        // an image to be in the attachments but not in the post itself
+        val path = key.toUri().path
+        if (path != null && postContent.contains(path)) {
+            var width = jsonImage.optInt("width")
+            var height = jsonImage.optInt("height")
+
+            // check if data-orig-size is present and use it
+            val originalSize = jsonImage.optString("data-orig-size")
+            val sizes = originalSize.split(",".toRegex()).dropLastWhile { it.isEmpty() }
+                .toTypedArray()
+            if (sizes.size == 2) {
+                width = sizes[0].toInt()
+                height = sizes[1].toInt()
+            }
+
+            this[key] =
+                ImageSize(
+                    width,
+                    height
+                )
+        }
+    }
+
+    fun getImageSize(imageUrl: String): ImageSize? {
+        return get(getKeyFromImageUrl(imageUrl))
+    }
+
+    private fun getKeyFromImageUrl(imageUrl: String) = UrlUtils.normalizeUrl(UrlUtils.removeQuery(imageUrl))
+
+    class ImageSize(val width: Int, val height: Int)
+
+    companion object {
+        private const val EMPTY_JSON = "{}"
+    }
+}