diff --git a/java/debugger/impl/src/com/intellij/debugger/impl/ClassLoadingUtils.java b/java/debugger/impl/src/com/intellij/debugger/impl/ClassLoadingUtils.java
index 22998e41c52b..b6577fef4477 100644
--- a/java/debugger/impl/src/com/intellij/debugger/impl/ClassLoadingUtils.java
+++ b/java/debugger/impl/src/com/intellij/debugger/impl/ClassLoadingUtils.java
@@ -39,7 +39,7 @@ public class ClassLoadingUtils {
 
   public static ClassLoaderReference getClassLoader(EvaluationContext context, DebugProcess process) throws EvaluateException {
     try {
-      // TODO: cache?
+      // TODO [egor]: cache?
       ClassType loaderClass = (ClassType)process.findClass(context, "java.net.URLClassLoader", context.getClassLoader());
       Method ctorMethod = loaderClass.concreteMethodByName("<init>", "([Ljava/net/URL;Ljava/lang/ClassLoader;)V");
       ClassLoaderReference reference = (ClassLoaderReference)process.newInstance(context, loaderClass, ctorMethod, Arrays
@@ -74,8 +74,13 @@ public class ClassLoadingUtils {
     }
   }
 
+  /**
+   * Finds and if necessary defines helper class
+   * May modify class loader in evaluationContext
+   */
   @Nullable
   public static ClassType getHelperClass(String name, EvaluationContext evaluationContext, DebugProcess process) throws EvaluateException {
+    // TODO [egor]: cache and load in boostrap class loader
     try {
       ClassLoaderReference classLoader = evaluationContext.getClassLoader();
       return (ClassType)process.findClass(evaluationContext, name, classLoader);
diff --git a/java/debugger/impl/src/com/intellij/debugger/settings/ImageObjectRenderer.java b/java/debugger/impl/src/com/intellij/debugger/settings/ImageObjectRenderer.java
index ff4cb6bc3f08..b6cb26dcdba3 100644
--- a/java/debugger/impl/src/com/intellij/debugger/settings/ImageObjectRenderer.java
+++ b/java/debugger/impl/src/com/intellij/debugger/settings/ImageObjectRenderer.java
@@ -91,12 +91,13 @@ class ImageObjectRenderer extends ToStringBasedRenderer implements FullValueEval
   private static Value getImageBytes(EvaluationContext evaluationContext, Value obj, String methodName)
     throws EvaluateException {
     DebugProcess process = evaluationContext.getDebugProcess();
-    ClassType helperClass = ClassLoadingUtils.getHelperClass(ImageSerializer.class.getName(), evaluationContext, process);
+    EvaluationContext copyContext = evaluationContext.createEvaluationContext(obj);
+    ClassType helperClass = ClassLoadingUtils.getHelperClass(ImageSerializer.class.getName(), copyContext, process);
 
     if (helperClass != null) {
       List<Method> methods = helperClass.methodsByName(methodName);
       if (!methods.isEmpty()) {
-        return process.invokeMethod(evaluationContext, helperClass, methods.get(0), Collections.singletonList(obj));
+        return process.invokeMethod(copyContext, helperClass, methods.get(0), Collections.singletonList(obj));
       }
     }
     return null;