Error resizing gif images with Webp enabled

[galiana]

Version of Dianoga ### 5.0.2

Environment description ### Dev Environment (Single VM), Sitecore 8.2 Initial release

What configs you have enabled

• Dianoga.DisableForSites.config
• Dianoga.Jpeg.config
• Dianoga.Png.config
• Dianoga.Strategy.MediaCacheAsync.config
• Dianoga.WebP.config

Reproducible steps (1... 2... 3...) that cause the issue

1. Upload a gif file

2. Render it with the format: https://server/-/media/image.gif?mw=xx&hash=xxx

What you expected to see, versus what you actually saw

I'm expecting a resized gif file, but i get the following error: Error! Unknown option '-resize'

Some extra information

Obviously, the external tool gif2webp.exe does not support resizing images (or at least the mentioned parameter) and in the pipeline processor Dianoga/src/Dianoga/Optimizers/Pipelines/DianogaWebP/WebPOptimizer.cs we are always sending the resize parameter if requested at line 22, no matter the actual optimizer used.

Relevant logs

3536 14:54:39 ERROR Dianoga: Unable to optimize due to a processing error! It will be unchanged.
Exception: System.InvalidOperationException
Message: "C:\inetpub\wwwroot\xxx\Website\App_Data\Dianoga Tools\libwebp-1.1.0-windows-x64\bin\gif2webp.exe -q 80 -lossy -resize 0 0 "C:\WINDOWS\TEMP\tmp6C0B.tmp" -o "C:\WINDOWS\TEMP\tmp6C0C.tmp" " exited with unexpected exit code -1. Output:
Error! Unknown option '-resize'
copy from the input to the output if present
-metadata ..... comma separated list of metadata to
-f ............... filter strength (0=off..100)
-kmax ............ max distance between key frames
-kmin ............ min distance between key frames
options
combined with -q, -m, -lossy or -mixed
lossless compression by default; can be
-min_size .............. minimize output size (default:off)
-m ............... compression method (0=fast, 6=slowest)
-q ............. quality factor (0:small..100:big)
or lossless compression heuristically
-mixed ................. for each frame in the image, pick lossy
-lossy ................. encode image using lossy compression
-h / -help ............. this help
Options:
gif2webp [options] gif_file -o webp_file
Usage:

-quiet ................. don't print anything
-v ..................... verbose
-version ............... print version number and exit

-mt .................... use multi-threading if available
version prior to M62 (inclusive)
-loop_compatibility .... use compatibility mode for Chrome
Valid values: all, none, icc, xmp (default)
Source: Dianoga
at Dianoga.Optimizers.CommandLineToolOptimizer.ExecuteProcess(String arguments)
at Dianoga.Optimizers.CommandLineToolOptimizer.ProcessOptimizer(OptimizerArgs args)
at Dianoga.Optimizers.OptimizerProcessor.Process(OptimizerArgs args)