Discord has an annoyingly small limit of 8MB file uploads, without a simple option to compress them during upload.
This app allows you to work around this limitation. By sharing an image to this app rather than directly to Discord, it will compress an image to under 8MB before taking you to the Discord share view.
This app requires that you have the official Discord app installed on your device.
Just share to the Compressor app from your share menu when sending a photo. The app will handle the rest.