That is displaying incorrectly. If no screenshot is added to the theme, it should show an SVG generated from the theme’s colour palette. It should also show the theme’s name below that image. That’s what is shown in the announcement here.
Looking at this previous topic, it looks like you might have added some custom CSS for that page. Perhaps that is interfering here? It also looks like your layout is incorrect as those theme cards are displaying too widely and wrapping incorrectly.
Could you check if you have some CSS affecting this page?
如果主题中没有添加屏幕截图，则应显示从主题的配色方案生成的 SVG。它还应在此图像下方显示主题的名称。这正是此处公告中所示的内容。
查看此先前的主题，看起来您可能已为该页面添加了一些自定义 CSS。也许这会干扰此处？另外，您的布局似乎不正确，因为这些主题卡片显示得太宽并且换行不正确。
您能否检查一下是否有影响此页面的 CSS？