Merge two images and add a separator between them

Question

I have two images of same width, how can I produce a third one, such that the first one is on top, and the second one is at the bottom , with an arrow between them ? Here's the result I want:

I come from kolourpaint and I have troubler understanding how to move a sub section of the image...

Currently :

1. I do gimp a.png b.png in the terminal to open the two images,
2. then I copy the first,
3. go to the second,
4. set canvas size to the sum of the heights + 100 pixels,
5. then I paste,
6. then I use the text mode to write a "↓",
7. then I select the "↓" and change the color and the size
8. Then I manage how to move the text...
9. Aaand I'm stuck if I want to decide after that, I actually wanted 80 pixels and not 100 in the previous step...

Answer 1

Keep everything in independent layers:

• Load the first image (top)
• Set the canvas size
• File>Open as layers, and add the second image, which will be an independent layer
• Use the Move tool to drag it down to the bottom of the canvas (you can use `View>Snap to canvas edges to make it easier)
• Add a third layer and create the arrow on it (using a Text layer as you did is one way)

That way you need to resize the image canvas you just have to move layers around. In practice you could also start with a canvas somewhat higher than necessary, position the bottom layer, and then use Image>Fit canvas to layers to set the canvas to the adequate size.

If you need a white background, you can add a new fourth layer (Layer>New layer) filled with white and drag it to the bottom of the stack in the Layers list. If you resize the canvas later, just delete it and recreate it.