My website had an image /wp-content/uploads/2020/12/abc.jpg.webp I deleted the image now it's showing a blank page with text "404 Not Found openresty/1.17.8.2"
I have installed the 404 to 301 plugin, it is supposed to redirect to the homepage. all other redirects are working fine but for images and attachments, it's not working. the white page that appears is not from my theme. please check this image
Redirecting 404 pages to homepage is an SEO anti-pattern: https://yoast.com/seo-anti-patterns-301-redirect-all-your-404s-to-your-homepage/
Instead of redirecting 404s to homepage, try to create a 404 page with a better design. Since you're using WordPress, there should be a bunch of plugins and themes that let you do that.
(BTW, if you really want to do that, try looking up your plugin settings or simply switch to another "404 to 301" or redirect manager plugin that support file/image redirects)
