Add Image constructor for typical use-cases with byte array content

[Copilot]

This PR adds a convenient constructor to the Image component that accepts byte array content and an image name, making it easier to create images from in-memory data.

New Constructor

public Image(byte[] imageContent, String imageName) {
    setSrc(DownloadHandler.fromInputStream(event -> {
        return new DownloadResponse(new ByteArrayInputStream(imageContent), imageName,
            URLConnection.guessContentTypeFromName(imageName), imageContent.length);
    }).inline());
    setAlt(imageName);
}

Features

• Automatic content type detection: Uses URLConnection.guessContentTypeFromName() to determine the MIME type based on the file extension
• Inline content disposition: Automatically sets the download handler to inline mode for proper image display
• Alt text assignment: Uses the image name as the alternative text for accessibility
• Seamless integration: Works with the existing DownloadHandler infrastructure

Usage Example

// Load image data from database, API, or generate programmatically
byte[] imageData = loadImageFromDatabase();
String fileName = "profile-picture.png";

// Create image component with one line
Image image = new Image(imageData, fileName);
layout.add(image);

This eliminates the need for developers to manually create DownloadHandler instances and DownloadResponse objects for the common use case of displaying images from byte array data.

Testing

Added comprehensive tests covering:

• Normal usage with proper file extensions
• Edge cases with missing file extensions
• Empty byte arrays
• Verification of alt text and src attribute assignment

Fixes #21967.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

• maven.vaadin.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --enable-native-access=ALL-UNNAMED -classpath /usr/share/apache-maven-3.9.11/boot/plexus-classworlds-2.9.0.jar -Dclassworlds.conf=/usr/share/apache-maven-3.9.11/bin/m2.conf -Dmaven.home=/usr/share/apache-maven-3.9.11 -Dlibrary.jansi.path=/usr/share/apache-maven-3.9.11/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/home/REDACTED/work/flow/flow org.codehaus.plexus.classworlds.launcher.Launcher clean compile -q -pl flow-html-components (dns block)
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --enable-native-access=ALL-UNNAMED -classpath /usr/share/apache-maven-3.9.11/boot/plexus-classworlds-2.9.0.jar -Dclassworlds.conf=/usr/share/apache-maven-3.9.11/bin/m2.conf -Dmaven.home=/usr/share/apache-maven-3.9.11 -Dlibrary.jansi.path=/usr/share/apache-maven-3.9.11/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/home/REDACTED/work/flow/flow org.codehaus.plexus.classworlds.launcher.Launcher test -q -Dtest=ImageTest -pl flow-html-components (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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