How to Compress an Image on a Mac: 3 Easy and Efficient Solutions

High-quality photos are great, but they can quickly fill up storage space and take a long time to upload and download. Compression reduces a picture’s file size, occasionally with a compromise of lowering image quality. Read on to discover how to compress an image on a Mac.

Fortunately, macOS provides users with a quick and easy way to compress images. If your device is updated to at least version 12 – known as macOS Monterey – or later, then you’ll be able to use this simple method. It allows you to compress a photo without using any applications, or even opening the image itself! Here’s how to compress a photo on a Mac.

1. Locate the image you want to compress in Finder.
2. Select the image.
3. Right-click on the selected image and hover over the Quick Actions option in the drop-down menu.
4. Select Convert Image.
5. You’ll be presented with three options:

   First, select which file format you wish to convert your image to. A good option is JPEG or JPG. These two file types were explicitly created to encode complex images. Unless your picture only contains text, JPG or JPEG is likely your best choice. Either of these file formats will have roughly the same quality as alternative formats like PNG, but the file size will be much smaller. It’s a win-win!

   Second, choose how large you want your image to be. You’ll have four options: Actual Size, Large, Medium, or Small. The first option, Actual Size, effectively means no significant change will be made to the size of your image. If you haven’t changed the format of your photo, choosing Actual Size will likely mean a minimal reduction in file size, if any. In that case, you can choose a smaller image size to reduce the file size of your photo. However, if you’ve changed the file format, you can choose Actual Size and still significantly reduce file size. The reduction will come from changing the file format rather than the literal size of the image. Choosing Actual Size will retain the most quality, while Small will result in the most significant loss in quality.

   Third, you have the option to preserve the metadata of your image. Metadata means all of the non-visual information associated with a photo. That could include the date and even the precise time the photo was taken. It could also include the specific location at which the photo was taken. To preserve this information, ensure the Preserve Metadata option is selected. If you want to remove this information from the photo, then uncheck the option. Removing metadata can be a good idea for privacy, especially if you plan on publishing the image online or sharing it widely, or if the metadata contains sensitive information you’d rather keep private.

6. To start the conversion, click the Convert to button. Your Mac will change the exact wording of this button depending on what file format you are going to convert to. For example, if you’ve selected JPEG, the button will read, Convert to JPEG.

That’s it! Your new, converted image will be saved in the same place as the file you converted. In fact, you might even see the new file pop up in your Finder window. Take a look at the new, smaller file size, and be satisfied in a job well done.

Another option for Mac users wanting to reduce a photo’s file size is the Preview application. Preview comes installed on all Macs, so you shouldn’t have to download any new software. If it isn’t on your Mac, for whatever reason, you can download it for free from the Apple Mac App Store.

1. Launch Preview. You should be prompted to open a file. Select the photo you wish to convert. If you don’t receive this prompt, click on the File option in the app’s header menu bar at the top of your screen, and then select Open.

   Note: You can also open a specific photo in Preview from Finder. Preview is often the default application for opening photos, which means that double-clicking on a photo file will usually open it in Preview. If Preview isn’t the default on your Mac, you can manually open a photo in Preview by right-clicking on a file, hovering over Open With, and selecting Preview. This will launch Preview if it isn’t open already.

Once your image is open in Preview, you have two options to reduce the file size. The first option is to export it at a lower quality:

1. Click on File in the app’s header menu bar and select Export.
2. You’ll have the option to change the file format. As in the previous method, select the format you’d like to convert your photo to.
3. You can also manually adjust the quality of your photo. Move the slider to the left to lower the quality of your image. Lowering the image quality will reduce the file size. Be careful when lowering the quality of an image, as going too far can make it blurry or pixelated. Consider what you are going to use the image for. If you’re sending a meme to a friend, for example, the quality usually doesn’t matter, and you can significantly lower it to save space. However, if you plan on printing the photo or using it as part of a presentation, you might want to keep the quality as high as possible. Fortunately, Preview should give you a preview (pun not intended) of your image’s new file size. Find the balance between quality and file size that works for you. 
4. Click the Save button to export your image.

You can use this option to convert multiple photos at once. Select all the images you wish to convert and open them all in Preview. Ensure all the thumbnails are selected by pressing Command + A. Then follow the above instructions as usual. The Export option should be replaced with Export Selected Images.

The second option is to resize your image manually:

1. Instead of exporting your image, click the Tools option in the app’s header menu bar, then select Adjust Size.
2. You’ll be able to change the height and width of your image. Both are measured in pixels. 
3. Adjust the size of your image and check the estimated new file size, which will be shown in the app.
4. When you’re satisfied with the file size, click on the OK button to complete the size adjustment.

Like Preview, the Photos app comes installed on all Macs, and you can download it for free if you don’t have it. The steps for converting a picture in Photos is similar to Preview:

1. Open the Photos app, find the photo (or photos) you wish to convert, and select it (or them). 
2. Click on File in the app’s header menu bar, then click Export, then select Export Photos. You can also achieve this with the shortcut Command + Shift + E.
3. You’ll be faced with an option labeled Photo Kind. Click on the arrow next to this to see the file formats you can convert to.
4. You can also adjust the quality and size of the photo, as in previous methods.
5. When you’re satisfied, click on Export. You’ll be prompted to choose where you want the photo(s) to be saved. When you’ve chosen the location, click on Export. Done!

For a more powerful conversion software, try using Movavi Video Converter. Unlike Preview or Photos, Movavi Video Converter can convert different file types, including photos, videos, and audio. It’s just as fast, if not faster, than Mac’s built-in options, and can even convert pictures with no loss in quality.