diff --git a/.gitignore b/.gitignore
index cbcdc08..6233d3c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ theme.py
 !/dist/drawingtraining
 /*.spec
 /build/
+/config.json
diff --git a/src/element/toolbar.py b/src/element/toolbar.py
index eadf2c8..fa270e4 100644
--- a/src/element/toolbar.py
+++ b/src/element/toolbar.py
@@ -8,6 +8,7 @@ from src.util import Util
 
 class Toolbar:
     def __init__(self, image_window, timer):
+        self.timers = []
         self.current_image = None
         self.current_original_image = None
         self.image_window = image_window
@@ -47,6 +48,7 @@ class Toolbar:
         self.timer_label.pack(side=RIGHT, ipadx=20)
 
     def display_new_timer(self):
+        self.timer = self.timers.pop(0)
         self.timer_label.configure(text=Util.format_seconds(self.timer))
         self.timer_check = self.image_window.window.after(1000, self.update_timer, self.timer)
 
@@ -59,7 +61,7 @@ class Toolbar:
             self.timer_check = self.image_window.window.after(1000, self.update_timer, current)
         else:
             self.image_window.window.after_cancel(self.timer_check)
-            if len(self.image_window.images) == 0:
+            if len(self.image_window.image.images) == 0 or len(self.timers) == 0:
                 self.image_window.window.destroy()
                 self.image_window.window.update()
                 return
diff --git a/src/entity/config.py b/src/entity/config.py
new file mode 100644
index 0000000..b90ae42
--- /dev/null
+++ b/src/entity/config.py
@@ -0,0 +1,49 @@
+import json
+import os
+from pathlib import Path
+
+from configparser import *
+import typing
+
+
+class Config(object):
+
+    _CONFIG_FILE: typing.Optional[str] = None
+    _CONFIG: typing.Optional[dict] = None
+
+    def __init__(self, config_file=None):
+        if config_file is None:
+            config_file = "config.json"
+
+        # Check that specified config file exists
+        if not os.path.exists(config_file):
+            Path(config_file).touch()
+            with open(config_file, 'w') as configfile:
+                json.dump({"session": []}, configfile)
+
+        Config._CONFIG_FILE = config_file
+
+        with open(config_file, 'r') as f:
+            Config._CONFIG = json.load(f)
+
+    @staticmethod
+    def save():
+        with open(Config._CONFIG_FILE, 'w') as configfile:
+            json.dump(Config._CONFIG, configfile)
+
+    @staticmethod
+    def get_config_file() -> str:
+        return Config._CONFIG_FILE
+
+    @staticmethod
+    def get_required_env_var(env_var: str) -> str:
+        if env_var not in os.environ:
+            raise Exception(f"Please set the {env_var} environment variable")
+        return os.environ[env_var]
+
+    @staticmethod
+    def get_required_config_var(config_var: str) -> str:
+        assert Config._CONFIG
+        if config_var not in Config._CONFIG:
+            raise Exception(f"Please set the {config_var} variable in the config file {Config._CONFIG_FILE}")
+        return Config._CONFIG[config_var]
diff --git a/src/entity/session/drawing.py b/src/entity/session/drawing.py
new file mode 100644
index 0000000..d98e5e7
--- /dev/null
+++ b/src/entity/session/drawing.py
@@ -0,0 +1,10 @@
+
+
+class DrawingElement:
+    def __init__(self, data=None):
+        if data is not None:
+            for key, value in data.items():
+                setattr(self, key, value)
+        else:
+            self.timer = 0
+            self.number_of_drawings = 0
diff --git a/src/window/app.py b/src/window/app.py
index 358cfcd..1b435a0 100644
--- a/src/window/app.py
+++ b/src/window/app.py
@@ -1,14 +1,22 @@
 from tkinter import *
 from tkinter import filedialog
 from pathlib import Path
+
+from src.entity.config import Config
 from src.util import Util
 from functools import partial
 from src.window.image import ImageWindow
+from src.window.session import SessionWindow
 
 
 class App:
     def __init__(self, root):
         super().__init__()
+        self.list_in_session = None
+        self.custom = False
+        self.config = Config()
+        self.session = None
+        self.session_window = None
         self.image_window = None
         self.root = root
         self.selected_folder = ""
@@ -36,12 +44,16 @@ class App:
             t = i
             new_button = Button(self.button_frame, text=Util.format_seconds(t),
                                 command=partial(self.set_timer_in_seconds, t))
-
             self.buttons.append(new_button)
             self.button_frame.columnconfigure(i, weight=1)
             new_button.grid(row=0, column=i, sticky=W + E)
             i += 1
 
+        new_button = Button(self.button_frame, text="Custom", command=self.custom_session)
+        self.buttons.append(new_button)
+        self.button_frame.columnconfigure(i, weight=1)
+        new_button.grid(row=0, column=i, sticky=W + E)
+
         self.launch_button = Button(root, text="Let's draw!", command=self.lets_draw, state="disabled")
         self.launch_button.pack(side="bottom")
 
@@ -49,6 +61,10 @@ class App:
         self.image_window = ImageWindow(self)
         self.image_window.lets_draw(self.found_images.copy(), self.timer)
 
+    def custom_session(self):
+        self.session_window = SessionWindow(self)
+        self.session_window.open()
+
     def select_folder(self):
         self.selected_folder = filedialog.askdirectory()
         self.found_images = list(
@@ -58,12 +74,13 @@ class App:
         self.check_lets_draw()
 
     def check_lets_draw(self):
-        if self.selected_folder != "" and len(self.found_images) > 0 and self.timer != 0:
+        if self.selected_folder != "" and len(self.found_images) > 0 and (self.timer != 0 or self.custom):
             self.launch_button.config(state="normal")
         else:
             self.launch_button.config(state="disabled")
 
     def set_timer_in_seconds(self, user_data):
+        self.custom = False
         self.timer = user_data
         for button in self.buttons:
             if button['text'] == Util.format_seconds(self.timer):
@@ -71,3 +88,11 @@ class App:
             else:
                 button.config(bg="gray85")
         self.check_lets_draw()
+
+    def set_custom(self, list_in_session):
+        self.custom = True
+        self.list_in_session = list_in_session
+        self.check_lets_draw()
+        for button in self.buttons:
+            button.config(bg="gray85")
+        self.buttons[-1].config(bg="blue")
diff --git a/src/window/image.py b/src/window/image.py
index 24f54e8..2c654d2 100644
--- a/src/window/image.py
+++ b/src/window/image.py
@@ -37,6 +37,7 @@ class ImageWindow:
 
     def on_closing(self):
         self.countdown_sound.stop()
+        self.window.destroy()
 
     def next_image(self):
         if self.toolbar.timer_check is not None:
@@ -46,8 +47,17 @@ class ImageWindow:
 
     def lets_draw(self, images, timer):
         random.shuffle(images)
+        timers = []
+        if self.app.custom:
+            for element in self.app.list_in_session:
+                for number in range(int(element.number_of_drawings)):
+                    timers.append(int(element.timer))
+        else:
+            for i in images:
+                timers.append(timer)
+
         self.image.images = images
-        self.toolbar.timer = timer
+        self.toolbar.timers = timers
         self.next_image()
 
     def play_countdown(self):
diff --git a/src/window/session.py b/src/window/session.py
new file mode 100644
index 0000000..58298a9
--- /dev/null
+++ b/src/window/session.py
@@ -0,0 +1,166 @@
+from functools import partial
+from tkinter import *
+
+from src.entity.config import Config
+from src.entity.session.drawing import DrawingElement
+from src.util import Util
+
+
+class SessionWindow:
+    def __init__(self, app):
+        self.total_row_time_value_label = None
+        self.down_button = None
+        self.up_button = None
+        self.timer_input = None
+        self.number_of_drawings_input = None
+        self.selected_element_index = -1
+        self.delete_button = None
+        self.add_button = None
+        self.app = app
+
+        self.window = Toplevel(app.root)
+        self.window.title("Custom session")
+        self.window.geometry("600x600")
+        self.window.protocol("WM_DELETE_WINDOW", self.save_on_closing)
+
+        self.left_column = Frame(self.window, width=300, height=600)
+        self.right_column = Frame(self.window, width=300, height=600)
+
+        self.left_column.grid(row=0, column=0, sticky="ns")
+        self.right_column.grid(row=0, column=1, sticky="ns")
+
+        self.list_in_session = []
+
+    def open(self):
+        list = Config._CONFIG['session']
+        if list:
+            self.list_in_session = [DrawingElement(e) for e in list]
+        self.update_session_list()
+
+    def update_session_list(self):
+        self.reset_list()
+        for i, session in enumerate(self.list_in_session):
+            bg = "blue" if i == self.selected_element_index else "grey85"
+            new_session = Button(self.left_column,
+                                 text=session.number_of_drawings + " drawings of " + session.timer + "s each",
+                                 command=partial(self.edit_element, i),
+                                 bg=bg
+                                 )
+            new_session.grid(row=i, column=0)
+
+        button_frame = Frame(self.left_column)
+        self.add_button = Button(button_frame, text="+", command=self.add_element)
+        self.add_button.pack(side=LEFT, padx=0, pady=0)
+
+        self.delete_button = Button(button_frame, text="-", command=self.remove_element)
+        self.delete_button.pack(side=LEFT, padx=0, pady=0)
+
+        self.up_button = Button(button_frame, text="^", command=self.up_element)
+        self.up_button.pack(side=LEFT, padx=0, pady=0)
+
+        self.down_button = Button(button_frame, text="v", command=self.down_element)
+        self.down_button.pack(side=LEFT, padx=0, pady=0)
+
+        save_session_button = Button(button_frame, text="v", command=self.save_session)
+        save_session_button.pack(side=LEFT, padx=0, pady=0)
+        button_frame.grid()
+
+    def reset_element(self):
+        for widget in self.right_column.winfo_children():
+            widget.destroy()
+
+    def reset_list(self):
+        for widget in self.left_column.winfo_children():
+            widget.destroy()
+
+    def update_element(self, index=None):
+        self.reset_element()
+        if index is not None:
+            self.selected_element_index = index
+            element = self.list_in_session[self.selected_element_index]
+            self.update_session_list()
+        else:
+            element = DrawingElement()
+
+        number_of_drawings_label = Label(self.right_column, text="Number of drawings")
+        number_of_drawings_label.pack()
+
+        self.number_of_drawings_input = Entry(self.right_column)
+        self.number_of_drawings_input.insert(INSERT, element.number_of_drawings)
+        self.number_of_drawings_input.bind("<KeyRelease>", lambda e: self.update_local_timer(e))
+        self.number_of_drawings_input.pack()
+        self.number_of_drawings_input.focus_set()
+
+        timer_label = Label(self.right_column, text="Time per drawing in seconds")
+        timer_label.pack()
+
+        self.timer_input = Entry(self.right_column)
+        self.timer_input.insert(INSERT, element.timer)
+        self.timer_input.bind("<KeyRelease>", lambda e: self.update_local_timer(e))
+        self.timer_input.pack()
+
+        total_row_time_label = Label(self.right_column, text="Total row time")
+        total_row_time_label.pack()
+        self.total_row_time_value_label = Label(self.right_column, text="")
+        self.total_row_time_value_label.pack()
+        self.update_local_timer()
+
+        save_button = Button(self.right_column, text="Save", command=self.save)
+        save_button.pack()
+
+    def update_local_timer(self, event=None):
+        self.total_row_time_value_label.config(
+            text=Util.format_seconds(int(self.timer_input.get()) * int(self.number_of_drawings_input.get()))
+        )
+
+    def remove_element(self):
+        self.list_in_session.pop(self.selected_element_index)
+        self.selected_element_index = -1
+        self.update_session_list()
+
+    def edit_element(self, i):
+        self.update_element(i)
+
+    def add_element(self):
+        self.selected_element_index = -1
+        self.update_session_list()
+        self.update_element()
+
+    def up_element(self):
+        self.list_in_session.insert(self.selected_element_index - 1,
+                                    self.list_in_session.pop(self.selected_element_index))
+        self.selected_element_index -= 1
+        self.update_session_list()
+
+    def down_element(self):
+        self.list_in_session.insert(self.selected_element_index + 1,
+                                    self.list_in_session.pop(self.selected_element_index))
+        self.selected_element_index += 1
+        self.update_session_list()
+
+    def save(self):
+        element = DrawingElement() if self.selected_element_index < 0 \
+            else self.list_in_session[self.selected_element_index]
+        element.timer = self.timer_input.get()
+        element.number_of_drawings = self.number_of_drawings_input.get()
+
+        if self.selected_element_index < 0:
+            self.list_in_session.append(element)
+        else:
+            self.list_in_session[self.selected_element_index] = element
+
+        self.update_session_list()
+        self.selected_element_index = -1
+        self.reset_element()
+
+    def save_on_closing(self):
+        # TODO save
+        self.window.destroy()
+
+    def save_session(self):
+        Config._CONFIG['session'] = []
+        for element in self.list_in_session:
+            Config._CONFIG['session'].append(element.__dict__)
+        Config.save()
+        self.app.set_custom(self.list_in_session)
+        self.window.destroy()