Added missing mobile drag drop image to docs from wekan.github.io git history.

Thanks to xet7 !

docs/DragDrop/Drag-Drop.md

@@ -10,7 +10,7 @@ It depends on role of user what drag drop is allowed https://github.com/wekan/we
 
 3. Use non-drag-handle area to to view other parts of board, by dragging board up/down/left/right, without moving any icons etc.
 
-<img src="https://wekan.fi/dragdrop/mobile-drag-drop.png" width="40%" alt="Wekan logo" />
+<img src="mobile-drag-drop.png" width="40%" alt="Mobile drag drop" />
 
 ## 2 or more external screens of desktop or mobile
 
@@ -43,4 +43,4 @@ Reorder with drag drop:
 ## Touch UI ideas
 
 - https://blog.la-terminal.net/godot-on-ipad-summer-update/
-- https://news.ycombinator.com/item?id=41415077
+- https://news.ycombinator.com/item?id=41415077