Update Stack images.

Author: trekhleb

src/data-structures/stack/README.fr-FR.md

@@ -20,7 +20,9 @@ autres articles en premier.
 
 Représentation simple de l'éxecution d'une pile avec des opérations empiler (push) et dépiler (pop).
 
-![Stack](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## Références
 

src/data-structures/stack/README.ja-JP.md

@@ -9,7 +9,9 @@
 
 プッシュとポップの例
 
-![Stack](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## 参考
 

src/data-structures/stack/README.ko-KR.md

@@ -16,7 +16,9 @@ _Read this in other languages:_
 
 다음은 push와 pop 연산을 실행하는 간단한 스택의 실행입니다.
 
-![Stack](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## 참조
 

src/data-structures/stack/README.md

@@ -8,24 +8,26 @@ _Read this in other languages:_
 [_Português_](README.pt-BR.md),
 [_한국어_](README.ko-KR.md)
 
-In computer science, a **stack** is an abstract data type that serves 
+In computer science, a **stack** is an abstract data type that serves
 as a collection of elements, with two principal operations:
 
 * **push**, which adds an element to the collection, and
 * **pop**, which removes the most recently added element that was not yet removed.
 
-The order in which elements come off a stack gives rise to its 
-alternative name, LIFO (last in, first out). Additionally, a 
-peek operation may give access to the top without modifying 
-the stack. The name "stack" for this type of structure comes 
-from the analogy to a set of physical items stacked on top of 
-each other, which makes it easy to take an item off the top 
-of the stack, while getting to an item deeper in the stack 
+The order in which elements come off a stack gives rise to its
+alternative name, LIFO (last in, first out). Additionally, a
+peek operation may give access to the top without modifying
+the stack. The name "stack" for this type of structure comes
+from the analogy to a set of physical items stacked on top of
+each other, which makes it easy to take an item off the top
+of the stack, while getting to an item deeper in the stack
 may require taking off multiple other items first.
 
 Simple representation of a stack runtime with push and pop operations.
 
-![Stack](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## References
 

src/data-structures/stack/README.pt-BR.md

@@ -18,7 +18,9 @@ vários outros itens primeiro.
 Representação simples de um tempo de execução de pilha com operações
 _push_ e _pop_.
 
-![Stack](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## Referências
 

src/data-structures/stack/README.ru-RU.md

@@ -8,14 +8,16 @@
 * **удаление (pop)**, последнего добавленного элемента.
 
 Дополнительная операция чтения головного элемента (peek) даёт доступ
-к последнему элементу стека без изменения самого стека. 
+к последнему элементу стека без изменения самого стека.
 
 Чаще всего принцип работы стека сравнивают со стопкой тарелок: чтобы взять вторую
 сверху, нужно снять верхнюю.
 
 Иллюстрация работы со стеком.
 
-![Стек](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## Ссылки
 

src/data-structures/stack/README.zh-CN.md

@@ -13,7 +13,9 @@
 
 栈的 push 和 pop 操作的示意
 
-![Stack](https://upload.wikimedia.org/wikipedia/commons/b/b4/Lifo_stack.png)
+![Stack](./images/stack.jpeg)
+
+*Made with [okso.app](https://okso.app)*
 
 ## 参考