As stated in our app listing, Crush.pics can automatically compress product, collection, and asset folder images. This means that images stored in the Settings > Files area of Shopify cannot be automatically compressed and this is a limitation of Shopify, not our app.
In the past, we've recommended manually compressing these images using free tools such as TinyPNG, which you still can do, or now you can compress them manually in the app using the same process.
Note: This will not auto-update the image on your site. You will need to upload it to the app, download it, and upload it to Shopify.
1. Open Crush.pics and click Images in the top right corner
2. Click Manual Upload in the top navigation bar
3. Select Conservative(Lossless) or Balanced(Lossy)
4. Drop images onto the uploader or click the uploader to select images from your computer
5. Select your image(s) and wait for the images to compress
6. Click Download next to the image
7. Right click on image and click Save Image As...