Fast websites attract more customers, sell more, and are treated better by Google in SEO.
I've looked at hundreds, maybe thousands, of Shopify stores. One ongoing speed issue is using too large of images, especially for product photos.
A customer Matt wrote me a question about image optimization and now I'm going to share my answer with you.
Google recommends we compress/re-size them to increase load time by 97%. That said, there are a LOT of image compression apps in the Shopify app store, and none of them have the sparkling review record of your products. Among complaints are that some of them completely scrub variants, or mess with the structured data, etc. I'm also wary of the resulting compression making our images look noticeably worse.
So my question to you is: is there one of these apps that you know (or have heard) is significantly better than the rest? Thanks in advance!
I don't have any advice for specific image compression apps.
What I do is to compress images before I upload them to my websites. The tool I use is trimage.org but it looks like it's for Linux only. I like it because I can give it an entire folder of images to work on and it'll automatically run the best optimizations it can.
There are a bunch of different image compressor programs and online tools you can use before uploading images to Shopify. Most of the compression algorithms work the same so you just need to find one that fits your budget and produces the same visual results. The nice thing about doing this outside of Shopify is that if the image gets messed up, it's just the image file and not any of the attached Shopify data.
This won't work for your existing product images though. For that you'll need to either use a Shopify app or compress and re-upload each image.
You might be able to take a full store backup including product images using Rewind (https://apps.shopify.com/backup), try an app, and then undo the changes if the app breaks any images. I've heard good things about Rewind so that could be a basic insurance policy for you. But test it first to make sure the backups actually get your images.
(Notice how I keep saying to test out an automated system in Shopify before trusting it? Let's just say there is a wide range of app quality in the store and some automations tend to run amok...)
If you do decide to re-upload your images by hand, start with the products that get the most sales and/or traffic. That way you can balance your limited time against the most impactful products.
Once automation that is safe and works is JSON-LD for SEO.
It's already automated the structured data creation for over a thousand Shopify stores and it's a risk-free option for any store.