Couple questions: are your photos in a gallery, or are you speaking of photos you're selling via square?
Depending on where you images "live," you may be able to enable right-click protection, which disables right-click/save.
Add a watermark to images you post. It shouldn't be huge, but it should be visible and difficult to remove in editing.
Export your images at low-rez; they should be large enough to display well in whatever window they'll be in. There are 96 pixels per inch, so if you're exporting for a 2' x 3' space, your export size is 192x288 pixels.
If you're exporting images from your phone, you can change the resolution before you shoot so images will be lower quality - meaning fewer pixels.
