The Interlace/Deinterlace plug-in for Gimp can swiftly interlace/deinterlace all layers in a multilayer image, enhancing its quality.
The interlace feature works by dividing the number of layers by two, merging two successive layers into even/odd numbered lines of one layer. You have the option to adjust the image height by dropping lines or doubling it and keeping all the lines.
On the other hand, the deinterlace feature separates even and odd numbered lines of each layer and stores them into two separate layers, thus doubling the number of layers. Lines in between are either interpolated or skipped, making it customizable and flexible. This feature allows you to create a new image with the original height or half of it.
Overall, I found the interlace/deinterlace plug-in to be a valuable tool for animators looking to work with multilayer images. It is easy to use and can be found under "< Image>/Filters/Animation/Interlace Tool".