GIMP/PS - How to save selection as pixel (remap) table?

Question

Using GIMP or Photoshop, either one of them. When selecting a part of the image using selection tool, how can i export this selection as a pixel map?

Answer 1

• Select>Save to channel
• In the Channels list, make sure the "Selection Mask Copy" channel is selected (it normakky should be, by default)
• File>Export: this will export the selection mask as an image (PNG or else)

To import back:

• File>Open as layers (loads the selection mask image on top of layers)
• In the Channels list, right click any of the R/G/B channels and "Channel to selection".
• Hide/remove the mask layer