1. Download image sources from here[drive.google.com]. You will find there PSD and PNG files.

2. Modify image as you want. Final result must be PNG image with transparency.
Warning: you must not resize the image or change duck size and position.

3. Create a folder in a convenient place for you and save all the finished PNG files there. After that, create a config.json file in this folder with the following contents:
where "path" value must be path to your image in this folder.

To add multiple images in single mod you should add more sections to the "files" like this:

You also must specify type of each image. You image will be displayed in the game in the category according specified type.
Supported types:

• "body" - main duck body
  
• "costume" - a costume that will append to the body
  
• "hat" - a hat that will append to the duck head
  
• "face" - something that will append to the dock face. For example cool glasses
  
• "gear" - something that will append to the duck wing

If you're making something that is not "body" type then you should make sure that your "costume", "face", "hat" etc. on the image is placed accurately relative to duck position.

4. Go to the game root folder and open "mods" folder. Copy your folder with images and config file to the mods folder.

5. Launch the game and click on the easel. If everything is done correctly, you will see your new duck skins.

You can upload your mods to the workshop using any tool you have. If you don't have it you can download a ready to use tool[drive.google.com]. In this tool you can see an example in the "WorkshopContent" folder.

If you downloaded a mod from the workshop, restart the game for the changes to take effect.

You can download mod example[drive.google.com] and put it to the "mods" folder to see how it works

Also you can download a test workshop item from this page.