Copy / Paste
Use Copy / Paste commands to exchange rectangular areas of the image with external applications or to copy a fragment of the image to another location within the same or different image.
This feature can come in handy in many situations, especially when you want to change some part of the image without recompressing the whole of it - insert a banner or copyright from a different source into a sequence of images, retouch a fragment in an external editor, etc.
You don't have to worry about the size of the area you copy out and back during external retouching - when the image gets saved, the final bitmap is compared to the original one, and the blocks that have not been changed will not be recompressed. So, regardless of the size of fragments you exchange, there will be no recompression to unchanged areas of the image, provided they didn't change their original location (there is no shift).
Select mode
To select a rectangular area to be copied:
1. Enter the Select mode by clicking the Select icon
on the main toolbar or select the Edit->Select item in the main menu or Select item in the context menu to enter the select mode.
You can use the S key as a shortcut for this command.2. Select an area by holding the primary mouse button down and dragging it. The selected area will be outlined by a dashed rectangular. Release the mouse button once you selected the desired area.
You can resize the selection by dragging a border or a corner with the primary mouse button down.
You can move the selection by dragging the inside of the selection with the primary mouse button down.
You can cancel the current selection by pressing Esc or clicking the Cancel button
on the Select panel or in the context (right-click) menu.You can also cancel the current selection and start a new one by holding the primary mouse button down and dragging it starting from the outside of the current selection.
To automatically align the top left corner of the selection area with the nearest block border, check the Align Selection by Block checkbox on the Select toolbar.
Copy command
Double-click on the selection, or click Copy Selection icon
on the main toolbar, Copy Selection button 
on the Select panel, or select the Edit->Copy item in the main menu to copy the selected area to the clipboard. This command is also accessible from the right-click context menu (Copy now) and via Ctrl+C and Enter shortcuts.Paste command
If there is an image in the clipboard you can paste it onto the current image by clicking the Paste icon
on the main toolbar or selecting the Edit->Paste item in the main menu or Paste item in the context menu. This command is also accessible via Ctrl+V shortcut. The content of the clipboard will be placed at the last selection position.You can move the pasted fragment around by clicking at a desired position outside the fragment or by holding the primary mouse button inside the fragment and dragging.
To accept the paste, double-click on the fragment, or press Enter, or click OK button
on the Paste panel or in the context menu.To cancel the paste, press Esc or click the Cancel button
on the Paste panel or in the context menu.