How to reduce image sizes in macOS without third-party apps
This article shows you how to reduce image sizes in macOS without downloading anything from the internet.
1. Open the image you want to reduce size with “Preview”.
2. Select “File” > “Export”.
3. Drag the slider next to “Quality” toward “Least” to reduce the image size. Note that the lower size your image is, the lower quality it has.
4. Click on the “Save” button to finish your work.