ImageSharp WebP transparency issues

[PerplexDaniel]

Which Umbraco version are you using? (Please write the exact version, example: 10.1.0)

13.3.2

Bug summary

There is a bug in ImageSharp that causes artifacts in transparent images when converted to WebP, see this GitHub issue. Is has already been fixed by the author in 3.1.4 (see his comment and his fix).

Please update SixLabors.ImageSharp to 3.1.4 in all applicable Umbraco versions to fix the issue.
I reproduced this on Umbraco 13.3.2 that uses SixLabors.ImageSharp 3.1.3.

For people who want to fix this issue now without waiting for Umbraco, you can install this newest version yourself for now:
dotnet add package SixLabors.ImageSharp --version 3.1.4

Specifics

No response

Steps to reproduce

Use the latest Umbraco LTS (13.3.2) to reproduce.

bunny.png

1. dotnet new umbraco -n WebP
2. cd WebP
3. dotnet run
4. Upload the attached image (bunny.png) to the media library
5. Go to the image URL (you can find it in the Media Library > Bunny.png > Info tab > Links)
6. Add ?format=webp to the end
7. Observe the broken image, which looks like this (note all the weird black bars that should be transparent).

Expected result / actual result

The WebP image should be fully transparent just like the original.

[github-actions]

Hi there @PerplexDaniel!

Firstly, a big thank you for raising this issue. Every piece of feedback we receive helps us to make Umbraco better.

We really appreciate your patience while we wait for our team to have a look at this but we wanted to let you know that we see this and share with you the plan for what comes next.

• We'll assess whether this issue relates to something that has already been fixed in a later version of the release that it has been raised for.
• If it's a bug, is it related to a release that we are actively supporting or is it related to a release that's in the end-of-life or security-only phase?
• We'll replicate the issue to ensure that the problem is as described.
• We'll decide whether the behavior is an issue or if the behavior is intended.

We wish we could work with everyone directly and assess your issue immediately but we're in the fortunate position of having lots of contributions to work with and only a few humans who are able to do it. We are making progress though and in the meantime, we will keep you in the loop and let you know when we have any questions.

Thanks, from your friendly Umbraco GitHub bot 🤖 🙂

[Zeegaan]

This should be fixed in #16616 😁

[Emetico]

I just updated from Umbraco CMS 13.3.2 to Umbraco CMS 13.4.1 and 13.4.1 uses Umbraco.Cms.Imaging.ImageSharp 13.4.1, but Umbraco.Cms.Imaging.ImageSharp 13.4.1 uses SixLabors.ImageSharp 3.1.3 and not 3.1.4.

[PerplexDaniel]

@Emetico Indeed, looking at NuGet it also says it uses SixLabors.ImageSharp v3.1.3:

And confirmed in Visual Studio:

Which is confusing because the PR mentioned by @Zeegaan does bump it to 3.1.4:

https://github.com/umbraco/Umbraco-CMS/pull/16616/files#diff-5baf5f9e448ad54ab25a091adee0da05d4d228481c9200518fcb1b53a65d4156R76

Perhaps it was reverted somewhere along the way?

[Zeegaan]

Heyo 👋
Yea seems that PR has gotten overriden in a merge somehow... 💾
We will make sure it goes in the next patch/minor, sorry about the confusion.. 😢

[DanDiplo]

Just a note that (in my experience) you need to delete the Media Cache to see the benefits of this.

[PerplexDaniel]

Just a note that (in my experience) you need to delete the Media Cache to see the benefits of this.

Yes absolutely, that's a good thing to point out. ImageSharp will generate a crop with the same parameters only once and will cache it in Umbraco/Data/TEMP/MediaCache so if you have any broken crops in there they will be served until that folder is emptied.