Sort of.... if the user is running Opera or Chrome they can copy and paste an image from a browser tab into DokuWiki using the
ImgPaste plugin.
Otherwise if you use namespace templates you can use the
upload Plugin - but I
suspect*¹ what you want is some sort of automagical method where the user:-
1. edits a page
2. clicks on a button
3. chooses an image source
the chosen image then (magically?) appears in the edited page (location and formatting also magically chosen).
You might want to look at a WYSIWYG editor, which might have similar capability (I don't know, haven't used them):-
* ckgedit
* WYSIWYG
* WYSIWYG nicedit
* fckg
* probably others
*¹ you don't describe your proposed workflow - "upload to page" is not as precise a description as you think. No doubt you can picture in your head the precise process, but I can't see that picture (words are good) :)