Note! Apng is deprecated format, Gimp 2.10 supports webp animations out-of-the-box.

APNG plug-in for Gimp 2.10 Windows 64x.
I haven't seen this for 2.10 so I'll post it for anyone who wishes to try out.
It doesn't overwrite anything, but be careful.

Installation:
1. Copy the dll file (libpng15-15.dll) to the Gimp 2\bin directory (C:\Program Files\Gimp 2\bin)
2. Create a new folder, called file-apng. Copy the exe file (file-apng.exe) in that folder and drop it to plug-ins folder (C:\Program Files\Gimp 2\lib\gimp\2.0\plug-ins)
3. Copy the plug-in-file-apng.ui file to the Gimp 2.10 ui directory (C:\Program Files\Gimp 2\share\gimp\2.0\ui\plug-ins).
4. Restart Gimp.

Create your animation layers.
File: Export as...select file type by extension from the list, PNG + APNG.
Skip the "extension mismatch" alert. Select compression level and make sure to tick on animation option.



Quick test.



Don't thank me, it's old apng build by Partha from 2011.

Update2: But how can I set the speed of layer changes? Now it "flyes" over my 8 pictures every 3000ms it should change to next layer for example. Is this possible?

Update: I worked!!! I edited every layer and clicked "layer to image size" and also set every layer mode to "normal" (some where "normal (v)")... after that it worked!!!

I tried it but after clicking save I get this warning

You can change frame timings either manually, by editing the layer attributes or by using a plug-in.
Combined mode:
Layername (200ms)
Replace mode:
Layername (200ms) (replace)

Read step 5 here:
https://www.gimp.org/tutorials/Simple_Animations/

I didn't know Gimp had native support for webp, thanks for that. Unfortunately this site won't let webp upload. Imgur also won't let upload webp. Does anyone know of a free image hosting site that allows webp upload?

Since WebP's Google format, my bet is Google Drive can host such file types. First 19Gs at Google are free. Personally have not used Google Drive. I do know OneDrive can host, pretty much, all types of files, but it may not see WebP files as images (ie, no preview).