Loading image with DecoderOptions { MaxFrames = 1 } loads multiple frames for attached png file

[danbystrom]

Prerequisites

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

ImageSharp version

3.1.4

Other ImageSharp packages and versions

Environment (Operating system, version and so on)

Windows 11

.NET Framework version

net7.0

Description

Loading an image with the following statement: using var img = await SixLabors.ImageSharp.Image.LoadAsync(new DecoderOptions { MaxFrames = 1 }, fileStream); should just load one frame, which is does for all images I have tested on, EXCEPT the attached one, where it imports all 42 frames.

Steps to Reproduce

Load the attached "duck.png" like this:

  using var fileStream = File.OpenRead(@"c:\temp\duck.png");
  using var img = await SixLabors.ImageSharp.Image.LoadAsync(new DecoderOptions { MaxFrames = 1 }, fileStream);
  Assert.AreEqual(1, img.Frames.Count);

Images