I understand you're looking for a free app that offers the same functionality as another app, Change Image on Hover. However, I'm not having any luck finding one that is free. While a free app for a function like this may not exist, I was able to find a more economical option - Second Image On Hover. If you need any help with this app, you can always reach out to the app developer through the contact information found in the Support section of their app's page.
Another option to accomplish this is by customizing your theme with custom coding, which would be a one-time task as opposed to a recurring monthly charge by using apps. While custom coding isn't something that's supported by our Theme Support, you can hire a developer to help you with this. If you need help finding a developer, we'd recommend taking a look at Shopify Experts. Shopify Experts is a directory of certified developers that have experience with custom coding and they'll be able to create a solution for your store.
Some third-party themes may also include a feature like this, which is something worth considering if the theme offers you additional features or designs that you can take advantage of. You can also try a paid theme using your store's content, so you can see how it fits with your business. That being said, did you get a chance to explore some of the third-party themes?
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