Can you share your site url? so that i can check and let you know.
Also share screenshot if possible where you exactly want to display thumbnail.
There is other free themes that do this better. Happy to have a chat and help you out if you want. Reach out below.
Thanks for your response,
Here is the link for the product page that I am having the issue on - https://bloomtheloom.com/products/unisex-shawl-collar-bathrobe
Thanks for your help in adnace.
Please add this code at the bottom of theme -> edit code -> assets -> theme.scss.liquid