When you return from a corporate photoshoot with 500 massive, high-resolution TIFF images, each file might consume 30 Megabytes of storage space. If you need to upload these images to a company website, you must resize every single one of them to 1000 pixels wide and convert them to lightweight JPEGs. Opening and exporting 500 images individually will literally take hours. To mathematically force the macOS neural engine to process the entire folder simultaneously in a matter of seconds, you must use the batch processing capabilities of the native Preview application.
Loading the Batch Array
The Preview application is not just a single-file viewer; it is designed to hold massive arrays of data in its active memory buffer.
- Open a Finder window and locate the folder containing all 500 massive images.
- Press Command + A to highlight every single file simultaneously.
- Right-click the highlighted block and select Open With > Preview.
Preview will launch, and you will see a single window. On the left side of the window, you will see a massive sidebar containing thumbnails of all 500 images.
Executing the Multi-Target Command
You must now explicitly instruct the Preview engine to target the entire array, not just the single image currently displayed on the screen.
- Click once on any thumbnail in the left sidebar.
- Press Command + A. Every single thumbnail in the sidebar will instantly highlight in blue. You have now locked the engine onto all 500 files.
- Look at the absolute top menu bar and click Tools.
- Select Adjust Size….
The mathematical control panel will appear. It will calculate the combined data size (e.g., Total Size: 15 GB). Change the unit to pixels, type 1000 into the Width box, and click OK.
The macOS neural engine will violently rip through the active memory buffer, calculating new pixel grids for all 500 images simultaneously. This may cause your Mac’s cooling fans to spin up rapidly.
Exporting the Batch Format
Once the resizing calculation is complete, the images are still in their original TIFF format. You must now batch-convert them to JPEG.
- Ensure all 500 thumbnails are still highlighted in blue.
- Click File > Export Selected Images…
- A dialog box will appear asking for a destination folder. Click the Options button at the bottom of the window to reveal the hidden format menu.
- Change the Format to JPEG.
- Click Choose.
The engine will instantly dump all 500 processed, resized, perfectly formatted JPEGs directly into your destination folder in a matter of seconds, completely bypassing hours of manual labor.