Gimp: How to swap the left and right sides of an image?

Question

I want to "cut" the image in half, move the original left half of the image to the right, and move the original right half of the image to the left. How can I do that using Gimp?

Answer 1

Easiest way: Layer > Transform > Offset.

Select "%" in the offset field and set the X to 50.

You're gonna get a live preview.

Sorry, my Gimp speaks italian... but it should be clear as well.

Answer 2

Assuming you image is a layer

• Duplicate the layer
• Make a rectangle selection over one half of the image. Instead of eyeballing the position you can edit the numbers directly in the tool options, and Gimp can do the math for you (you can use formulas in input fields) so if your image is 1200Wx800H you can get a selection with:

• Layer > Crop to selection
• Select > Invert (selects the other half)
• Switch to the other layer and Layer > Crop to selection

• Use the move tool to move them with:
  • one hint: use View > Snap to canvas edges to help you position them
  • one warning: make sure the Move tool has Move the active layer checked (or use Shift-click to start Moving) and select the layer you want to move in the Layers list, otherwise you'll likely always move the topmost layer.

Answer 3

In case you need exact halves (and assuming an even number of pixels of course), you can do this with a guide

1. Do Image > Guides > New Guide by percent, choose "Vertical" and set it to 50%

2. To split the Image you can either do as Xenoid suggests, or do Image > Slice Using guides.

3. Finally, in each of the sliced images, select all and copy, then back in your main image do Edit > Paste As > New Layer, move into position using snapping. And repeat for the other slice.