Resizing an image on Mac is very easy using the Preview app. It is a free editor that comes pre-installed on all Macs. Preview can be used to easily crop images for the purpose of resizing them without the need to install additional software. Read on to find out how to manage image size, eliminate unnecessary areas and change their resolution using Preview.
Steps
Method 1 of 2: Resize an Image with Preview
Step 1. Navigate to the folder that contains the image to edit
This method is useful for changing the size of an image. If you need to crop certain areas of an image in order to reduce its size, read this article.
To search for an image by name or tag, open a Finder window, then click on the magnifying glass icon located on the menu bar. Type the criteria to search for in the bar that appears and press the Enter key. The list of results will be displayed
Step 2. Drag the image you want to edit onto the Preview app icon located on the Dock or in the Finder window
The image in question will be opened in the Preview window.
Alternatively, you can click on the image in question with the right mouse button, choose "Open with" and finally choose "Preview"
Step 3. Click on the button to activate the edit mode
It features an icon depicting a square and a pencil. A new toolbar will appear at the top of the Preview app window.
Step 4. Click on the "Tools" menu, then choose the "Adjust Size" item
Step 5. Change the resolution
The resolution of an image is measured in pixels per inch (or in "dots per inch" or "dpi"). If you need to print an image or just want it to have the highest visual quality level possible, consider increasing its resolution.
- If the image is to be used within a website or social network, such as Facebook, the default value (72) is optimal. If the image has a high resolution, reducing it will allow you to reduce the file size on disk.
- If you need to print the image in question in a high quality format, for advertising purposes or for other forms of commercial communication, set the dpi value to at least 600. Note: in this way the corresponding file size will increase in size. meaningfully.
- To print photographs with acceptable quality, 300 dpi is more than enough. The file size on disk will be much larger than using a 72 dpi resolution, but the visual quality you get will pay off.
Step 6. Type the new dimensions that the image should have in the appropriate text fields
The larger the image size (width and height), the greater the disk space occupied by the corresponding file.
- It may be useful to change the units of measurement to have more control over the changes you will need to make to the image size. For example you can choose the "centimeters" option to be able to specify the new dimensions in centimeters. Click on the drop-down menu next to the "Width" and "Height" text fields to make your choice.
- Alternatively, you can choose to resize the image to a percentage of its current size. In this case, choose the "Percentage" option from the drop-down menu under consideration.
Step 7. Select the "Scale Proportionally" or "Scale Proportionally" checkbox to avoid warping the image
This is an optional step, but using this option will allow you to change only the width or height of the image, as the other value will be automatically calculated based on the one entered. This way you can be sure that the original aspect ratio will not be changed.
Step 8. Click the OK button to view the image with the new dimensions indicated
If you are not satisfied with the result, press the key combination ⌘ Cmd + Z to undo the changes.
Step 9. Press the key combination ⌘ Command + S to save the new changes
After completing the changes, remember to save your work.
- If you want to save the resized image with a new name, click on the "File" menu and choose the "Save As" option.
- If after saving the changes you have noticed that you have made a mistake, go to the "File" menu, choose the "Revert to" item, then select the "Browse all versions" option. At this point, choose the version of the image to restore.
Method 2 of 2: Cropping an Image with Preview
Step 1. Click on the button to activate the edit mode
It features an icon depicting a square and a pencil.
Step 2. Click the button with a dotted outline rectangle visible on the toolbar, then choose the "Rectangular Selection" option
Step 3. Draw a selection area that includes the portion of the image you want to keep
When you release the mouse button you will see a rectangle with dotted edges appear on the screen that will enclose a portion of the image inside it.
Step 4. Click on the Crop button
This way all sections of the image that are outside the selection area will be deleted.
- At this point you can resize the image area you have kept as you would any other photo.
- If you are not satisfied with the result, press the key combination ⌘ Cmd + Z.
Step 5. Press the key combination ⌘ Cmd + S to save the new changes
- If you want to save the edited image to a new file without overwriting the original one, click on the "File" menu and choose the "Save As" option.
- If after saving the changes you have noticed that you have made a mistake, go to the "File" menu, choose the "Revert to" item, then select the "Browse all versions" option. At this point, choose the version of the image to restore.
