ECM Bulk Image Resizer helps your store's images load faster and rank better. It can:
compress images so files are smaller (without changing the format),
make images a consistent 1:1 square,
resize images to a maximum width,
fill in alt text from a template,
rename image files to descriptive, SEO-friendly names.
It works on your product images, and optionally on collection and theme images (turn them on in Settings). Images in Shopify's Settings > Files (homepage banners, blog and page images) can't be optimized by any app — this is a Shopify limitation.
Not sure where to start with your store? Chat with us — we'll suggest the right settings for your images.