Thank you very much for providing this tool～
If image path contains uppercase characters, a FileNotFoundException will occur. For example: c://TEST.png -> c://test.png. If the file path requires lowercase, make sure it is in the necessary location

The generated GIF file is too large to be compressed? Or can you only make the source file smaller? If you can, can you guide me?

Is there any way to compress the generated gif, it is much bigger than the original images size(I mean the file size instead of image resolution/size), almost 10 times bigger, any optimized solution?

Original image:

When on a rotation and exported to gif:

When set to a background and transparency color of Black and perfect match as false:

To use this project in JPMS modular builds, an automatic module name would be helpful; see the following blog post for context:

http://branchandbound.net/blog/java/2017/12/automatic-module-name/

The idea would be to add the following to the pom.xml, inside the build/plugins section:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-jar-plugin</artifactId>
  <version>3.2.0</version>
  <configuration>
    <archive>
      <manifestEntries>
        <Automatic-Module-Name>com.madgag.gif.fmsware</Automatic-Module-Name>
      </manifestEntries>
    </archive>
  </configuration>
</plugin>

I was trying to test decode and encode a gif and compare with original input file, I found the size drops and quality drops. is encode a lossy process? Or I miss something? below is my encode code

encoder.setRepeat(0);
      encoder.setDelay(decoder.delay);
      encoder.setDispose(decoder.dispose);
      encoder.setQuality(1);
      encoder.setSize(decoder.width, decoder.height);
      for (int i = 0; i < decoder.getFrameCount(); i ++) {
        encoder.addFrame(decoder.getFrame(i));
      }

      encoder.finish();
      assertEncodedImageIsEqualTo(gif);

Both the README and the project description contain a link to http://www.fmsware.com/stuff/gif.html, a site which is now owned by a SEO company. The website displays pages filled with garbage.

I suggest replacing any occurrence of http://www.fmsware.com/stuff/gif.html by http://www.java2s.com/Code/Java/2D-Graphics-GUI/AnimatedGifEncoder.htm which is more informative. In fact, any page that does not feed the SEO troll would be preferable.