diff --git a/file_io/include/aare/File.hpp b/file_io/include/aare/File.hpp
index 7fc091fc..2ed9a034 100644
--- a/file_io/include/aare/File.hpp
+++ b/file_io/include/aare/File.hpp
@@ -1,5 +1,5 @@
 #include "aare/FileInterface.hpp"
-class File : public FileInterface {
+class File {
   private:
     FileInterface *file_impl;
 
@@ -10,19 +10,20 @@ class File : public FileInterface {
     //  - a appending (appends to existing file)
     // TODO! do we need to support w+, r+ and a+?
     File(std::filesystem::path fname, std::string mode);
-    Frame read() override;
-    std::vector<Frame> read(size_t n_frames) override;
-    void read_into(std::byte *image_buf) override;
-    void read_into(std::byte *image_buf, size_t n_frames) override;
-    size_t frame_number(size_t frame_index) override;
-    size_t bytes_per_frame() override;
-    size_t pixels() override;
-    void seek(size_t frame_number) override;
-    size_t tell() override;
-    size_t total_frames() const override ;
-    ssize_t rows() const override ;
-    ssize_t cols() const  override ;
-    ssize_t bitdepth()  const override ;
+    Frame read();
+    Frame iread(size_t frame_number);
+    std::vector<Frame> read(size_t n_frames);
+    void read_into(std::byte *image_buf);
+    void read_into(std::byte *image_buf, size_t n_frames);
+    size_t frame_number(size_t frame_index);
+    size_t bytes_per_frame();
+    size_t pixels();
+    void seek(size_t frame_number);
+    size_t tell() const;
+    size_t total_frames() const;
+    ssize_t rows() const;
+    ssize_t cols() const;
+    ssize_t bitdepth()  const;
     File(File &&other);
 
 
diff --git a/file_io/src/File.cpp b/file_io/src/File.cpp
index 6e0b893e..e449bfeb 100644
--- a/file_io/src/File.cpp
+++ b/file_io/src/File.cpp
@@ -18,7 +18,7 @@ size_t File::frame_number(size_t frame_index) { return file_impl->frame_number(f
 size_t File::bytes_per_frame() { return file_impl->bytes_per_frame(); }
 size_t File::pixels() { return file_impl->pixels(); }
 void File::seek(size_t frame_number) { file_impl->seek(frame_number); }
-size_t File::tell() { return file_impl->tell(); }
+size_t File::tell() const{ return file_impl->tell(); }
 ssize_t File::rows() const { return file_impl->rows(); }
 ssize_t File::cols() const { return file_impl->cols(); }
 ssize_t File::bitdepth() const { return file_impl->bitdepth(); }
@@ -26,6 +26,10 @@ File::~File() {
     delete file_impl;
 }
 
+Frame File::iread(size_t frame_number) {
+    return file_impl->iread(frame_number);
+}
+
 File::File(File &&other) {
     file_impl = other.file_impl;
     other.file_impl = nullptr;