Upgrading your Shopify theme can be risky but sometimes that risk is warranted, especially if it will help conversions.
One good reason to upgrade is because your theme is using too small of product images.
Some people think Shopify resize product images automatically but it's actually your theme that's creating the small image.
What happens is that your theme is coded to use a specific image size so the theme is "asking" Shopify to resize the images to a specific size for a specific page.
Shopify supports images up to 4472x4472px but the majority of older themes used the old "grande" image size which is 600x600 pixels. In the 2000s 600 pixels was enough for everyone but modern device displays are now running 4K/5k/high-DPI/oh-my-DPI.
That makes 600x600 woefully small for a full-sized, zoomed-in image.
Which means that your customers might struggle to see your product so they'll leave and buy from someone else.
This old "grande" size still works but Shopify has been encouraging themes to stop using that style.
If this is the case your best best is to contact your theme vendor and see about an update. An update might also automatically use a larger size so you won't need to re-size any of your images by hand. And some themes have used
(And don't go the other way and use the biggest images you have, that'll slow down your page which will also hurt conversions. Think Goldilocks, one in the middle that is just-right.)
Most Shopify themes don't quality for Google's Rich Results so they lose out on highly visible SEO enhancements.
JSON-LD for SEO provides high-quality data that will let your store qualify for Rich Results. Often times faster than the industry averages.
Eric Davis