Casino game thumbnails should behave like profile pictures to stand out clearly...

https://future-wiki.win/index.php/How_to_Design_the_Art_and_Title_as_One_Composition_for_Impactful_Thumbnails

Casino game thumbnails should behave like profile pictures to stand out clearly on small screens. Focus on one strong focal point to capture attention quickly. Use high contrast colors and bold shapes to pop against any background