[WEBP] Creating lossy webp from this png produces corrupted webp file

[mikethea1]

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of ImageSharp
• I have verified if the problem exist in both DEBUG and RELEASE mode
• I have searched open and closed issues to ensure it has not already been reported

ImageSharp version

3.1.8

Other ImageSharp packages and versions

n/a

Environment (Operating system, version and so on)

Windows 11 x64, also reproduced on Amazon Linux x64

.NET Framework version

8

Description

When this .png file is converted to .webp using ImageSharp, it produces a corrupted webp image:

Screenshot of corrupted webp file as viewed in chrome:

I did look at #2068 which seemed like a similar issue but the problem ended up being their environment. In my case, I'm able to reproduce with a minimal reproduction as shown below. I won't rule out that I'm doing something wrong, but I'm not seeing anything and my webp conversion code works beautifully otherwise.

EDIT: I think this is caused by the image having dimensions greater than the max webp supports (16383). So the issue might be more one of argument validation/throwing a clear error message rather than a flaw in the encoding algorithm.

Steps to Reproduce

Repro code:

var path = @"path\to\repro.png";
using var image = SixLabors.ImageSharp.Image.Load(path);
using var outputStream = File.OpenWrite(path + ".webp");
image.Save(outputStream, new WebpEncoder { Quality = 75, Method = WebpEncodingMethod.Fastest, FileFormat = WebpFileFormatType.Lossy });

Images

Input and output files (had to zip since neither would upload directly):

repro.zip

[JimBobSquarePants]

Thanks @mikethea1 for the repro and investigation. Yes, we are missing some validation there. We have it in place for lossless encoding only.

[mikethea1]

Thanks for the quick fix @JimBobSquarePants !