How to Resize Pictures (for Macs)

If you have ever sent or received photos via email or attached them somewhere on the web, you know that image size can be a problem. Some websites only allow small images so they load faster and consume less memory, and getting an email with a huge image can be very annoying. Resizing an image on a Mac is very easy to do once you know how to do it, and requires no extra software other than what comes with the computer.


1. Open Finder by clicking on the Mac icon in the dock.

2. Navigate to the folder which contains the image you want to resize.

3. Command-Click the image, and hover your cursor over “Open With”.

4. From the drop down menu, select “Preview”. The image will open in a new window.

5. With the Preview window selected, click on “Tools” in the top bar to drop down that menu and select “Adjust Size”. A window will slide down over the image.

6. Highlight the “Width” field, and enter the desired width of the image. Unless you have unselected the “Scale proportionally” box, the height should change accordingly. At the bottom of the adjustment window, it will display the resulting size in KBs of GBs.

7. Click “OK”. The image should change size in the Preview window.

8. Drop down the “File” menu, found in the top bar, and select either “Save” or “Save As”. “Save” will replace the original image with the resized version, whereas “Save As” will allow you to save it as a new image under a new name.

9. Quit out of preview by dropping down the “File” menu, and select “Quit Preview”. You’re done!


  • For web use 100-200 KBs usually is ideal, depending on how large you want the image displaying.


  • If you select “Save” instead of “Save As”, you will lose the original image.
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This entry was posted on Friday, January 20th, 2012 at 3:16 pm and is filed under Technology. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.