You can check your theme’s settings
Go to Customize → Theme setting → Product Grid
then you can adjust the image to the size you want.
You also need to check the original image size, if the image size is too large, the theme will automatically adjust to the appropriate size.
Or you can also use applications that allow to maximize images.
Besides, you can edit the theme code
Topic summary
Consistent product image sizing for horizontal and vertical poster mockups in the Shopify “Testament” theme. Two screenshots are central: one shows the current mismatched sizing, the other the desired uniform look.
Recent guidance:
- Share the store URL to enable specific troubleshooting.
- In Shopify admin: Customize → Theme settings → Product Grid, adjust image display settings for uniform sizing.
- Check original image dimensions and aspect ratios; large or varied sizes may be auto-adjusted by the theme and cause inconsistency.
- Consider apps that standardize/resize images across products.
- As a last resort, edit the theme code for precise control over image containers and aspect ratios.
Notes:
- “Product Grid” refers to the theme’s configuration for how product images are sized and displayed in listings.
- Using consistent aspect ratios (e.g., same width-to-height) across all product images improves uniformity.
Status: No resolution yet; awaiting the store URL and results from adjusting theme settings.