The interleave-layers
script requires that the stack of layers and the inserted layers all have the same size. So you need to:
- Use
Image>Canvas size
to enlarge the animation canvas to the final size, and select Resize layers
>All layers
. You can position your layers in the bigger canvas at that point (Center
button, or drag them in the preview widget).
- Add a layer to the image (it will normally assume the size of the canvas), filled with the background color
- Make that layer invisible
Use Image>Interleave layers>Interleave layers (sprite mode)
with:
Layer
: the background layer
Opacity
: 100%
Mode
: Normal
Merge
: Yes
This creates a new image.
Note that if your layers have no alpha channel, and the background color in the toolbox swashes is already set to your grey-like color, then just the first step of all this (Image>Canvas size
) will be necessary, since Gimp extends alpha-less layers with the background color.