From Dashboard, click
COMPRESS IMAGES OR ALT TEXTS
Select Image type
Collection cover images
And then select Collection type(there are few choices depending on Image type you selected)
All(Blogs/Products/ and so on)
Next, you need to select Action type.
Seo tools(alt text update)
You can select Lossy or Lossless and click
Lossless - better quality, but smaller compression(default)
Lossy - lower quality, but better compression
If you check this option, all images will be converted to JPG format. It can reduce the image file size up to 85%.
Select one of the pre-made templates, or use a custom template.
Alt text is not applied for asset images.
If you check
This task will be run every day at the same time(will update new images)