I'm using the Debut Theme, and I discover that the variant images won't change on matter on Desktop or mobile phone. They worked in the past but not now. The Shopify Official said that my developer may had edited some codes which cause this problem. And I tried this morning to add a complete new theme of Debut and upload a product to test, the variant images change! So would you please help me to discover the solution of this issue, because I can't replace the edited theme all of sudden for whom a lot of endeavor have been put into Anyway, thank you all .... https://phomemo.com/
Welcome to Shopify Community. My name is Olivia and I work here.
Thank you so much for connecting with us and sharing your issue. Based on your troubleshooting steps, it definitely appears as though some of the custom code added by your developer broke the variant recognition on your product pages.
I ran some extra tests, and I ruled out any apps as the cause of this code break. The more we know about what didn't cause this - the closer we get to finding the root cause! For starters, have you connected with your developer yet and brought this to their attention? Since this is custom work, they will know the code they added best and be able to revert changes without breaking the effect of your custom product page.
That should definitely provide further insight if your developer is unable to identify the code. I also invite our code experts to take a deeper look at your theme and provide their code recommendations.
Thank you so much for your great detailed advice. And I did as you said, I duplicated my theme, then I check the code in page liquid. However, I didn't find any older version of this liquid, which means the product page hasn't been modified at all? Please help me, I'm completely confused......
Thanks for following up with me, @Mark999.
Though this method isn't guaranteed to work the page.liquid would be for your general store pages. For the product page, look for something along the lines of product.liquid.