Bug report

Trying to generate thumbnails for psd/html file that are supported via ImageMagick.

• If source is loaded from local file via vipsthumbnail, everything works fine;
• If source is piped via stdin or loaded from file via thumbnail_source, it will fail with VipsForeignLoad: source is not in a known format

test.psd.zip

To Reproduce

1. unzip test.psd.zip, you will get test.psd;
2. execute vipsthumbnail test.psd, thumbnail can be generated;
3. execute cat test.psd | vips thumbnail_source '[descriptor=0]' .png 100, got error VipsForeignLoad: source is not in a known format;
4. execute vips thumbnail_source '[filename=test.psd]' .png 100, got error VipsForeignLoad: source is not in a known format;

Expected behavior
Thumbnail can be generated no matter how to specify the source.

Actual behavior
Format cannot be detected if loading ImageMagick supported source from thumbnail_source.

Screenshots

Environment
macOS 15.5

Additional context
Add any other context about the problem here.