Mobile Images appear small even after adjusting setting

Hello,
I am using the free version of your plugin. I am ready to purchase the pro version, however i am facing issue with the mobile images of the product page are not appear large. I have set the setting for mobile to Gallery Width 1000, tried 420, 480. Still the image and the images thumbnail gallery appear really small. I am using a theme called konsept theme by QI. Pleaese advice at the earliest. Ready to purchase the pro version after you can tell me if this problem can be fixed.

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