The icon-holder has a white background set which results in an awkward drop shadow. On the blog/webinars page, looking at the icons used here and lower on the page for the subjects I notice that there are varying formats and transparencies used. Some are webp, some png, some have transparency and some do not. I believe this background should be removed and the images should be exported correctly (example for how this looks once fixed on the right)
https://github.com/openstax/os-webview/blame/4ad6767a93d70698a7dec778cfa14904f62fc8b8/src/app/components/explore-by-subject/explore-by-subject.scss#L19

The icon-holder has a white background set which results in an awkward drop shadow. On the blog/webinars page, looking at the icons used here and lower on the page for the subjects I notice that there are varying formats and transparencies used. Some are webp, some png, some have transparency and some do not. I believe this background should be removed and the images should be exported correctly (example for how this looks once fixed on the right)
https://github.com/openstax/os-webview/blame/4ad6767a93d70698a7dec778cfa14904f62fc8b8/src/app/components/explore-by-subject/explore-by-subject.scss#L19