sometimes it would be helpful to use the coordinate picker tool of the 2D Drawing toolbox to be able to extract a subimage of an image displayed in the frontend.
The problem here ist that the picker tool gives you x,y coordinates with y positive direction growing from bottom to top. Whereas ImageTake first needs row indices growing top to bottom followed by column indices.
The following function provides most of what is needed:
ImageTaker accepts 2 paramters the first one is the source image, the second is the x,y coordinate pair specifying the subimage.
So the procedure is the following: pick twice inside the source image using the coordinate picker tool, copy the coordinates by pressing CTRL-C, paste the coordinates CTRL-V to the function above as second parameter, feed the source imgage as first parameter e.g. by referencing an output cell containing the image by %nnn and evaluate it.
this gives you something like this:
which will evaluate and display the desired subimage.