How to reduce photo size on Mac

You need to resize some photos to be able to upload them to your website, but having recently switched to Mac you don’t know which programs to use to do this? What if I told you that you can do everything without downloading even an application from the Internet? No kidding. If you want to learn how to reduce the size of a Mac photo , all you have to do is take advantage of the potential of one of the tools included “standard” in macOS.

Obviously, in the event that what is already offered by the “bitten apple” computers is not satisfied (or in any case if a valid alternative is sought), you can always and in any case resort to the use of third-party tools. Find everything explained in detail below.

So? May I know what are you still doing standing there? Position yourself comfortably in front of your trusted computer and immediately start concentrating on reading what is reported below. I’m sure that in the end you will be able to tell you that you are very happy with what you have learned and that you will even be ready to say that it was actually a real piece of cake. How about we bet?


  • How to reduce photo size on Mac
  • Programs to reduce photo size on Mac
    • XnConvert
    • GIMP
    • Other solutions to reduce photo size on Mac
  • How to reduce photo size on Mac online
    • ILoveIMG
    • More solutions to reduce photo size on Mac online

How to reduce photo size on Mac

As I said at the beginning, to reduce the size of a photo on Mac you can first take advantage of the features offered by  Preview , the application included in macOS to view and edit images and PDFs. You will find it already installed on your computer, you don’t need to download it from the Internet.

To resize a photo with Preview, all you have to do is open the file of your interest by double-clicking on it. If doing so starts another program, it is because Preview is no longer the one set as the default . To fix it, right click the mouse on the photo, select the Open with item from the context menu and then the Preview one .

Now that you are viewing the image, to be able to resize it by acting on the resolution, click on the Tools menu at the top left and select the Adjust size item from the latter. In the window that opens, type the width or height dimensions to which you want to reduce the photo in the appropriate fields and click on the OK button to save the changes. If you don’t want to resize the images while keeping their aspect ratio intact, uncheck the item Resize proportionally and continue as I have already explained.

Don’t want to reduce the resolution of an image, but just want it to weigh less? If so, to do so, click on the File menu at the top left and select the Export item from the latter, then choose the  JPEG item from the Format drop-down menu  in the new window that has opened and use the  Quality adjustment bar  to select the quality level at which to save the image. Naturally, the lower the quality selected, the lower the weight of the file obtained.

In addition to reducing the size of one photo at a time, with Preview you can also resize multiple images at once. To do this, after opening the first photo whose size you want to change, then expand the View menu at the top left and select the Thumbnails item  from the latter, in such a way as to bring up the sidebar with the thumbnail of the selected image.

At this point, drag all the images you want to resize to the Preview sidebar and select them by pressing the cmd+a key combination on the Mac keyboard. Subsequently, click on the Tools menu at the top left and choose the item Adjust size from this last, so type the dimensions you want to apply to all the selected files in the window that opens.

If you don’t want to change the resolution of the photos, but just “lighten them”, right-click with the mouse on any of the thumbnails and select the Export as  item from the menu that appears. In the window that opens, select JPEG from the Format drop-down menu , then proceed as I indicated a few lines further up for the individual photos.

Programs to reduce photo size on Mac

In the event that the default functions of macOS do not satisfy you, you can consider turning to third-party programs to reduce the size of a photo on Mac , as in the case of those that I have provided below, in my opinion among the best in the category.


The first of the useful programs to reduce the size of a photo on Mac that I think you should consider is  XnConvert . It is a cost-free solution useful for basic image editing operations. Among the various functions offered, it also integrates some useful ones for carrying out the operation covered by this guide, intervening on the resolution.

To download XnConvert on your Mac, visit the  program’s website , scroll down the displayed page and click on the  Mac DMG 64bit button .

When the download is complete, open the  .dmg package obtained and drag the XnConvert icon to the macOS Applications  folder , then right-click on it and select the Open item from the context menu, in such a way as to start the application, however going around the Apple limitations towards non-certified developers (operation that must be performed only at the first start).

Now that you see the XnConvert window on your desktop, drag the photos you want to resize onto it and click the Actions tab . Alternatively, click on the Add file button  or on the Add folder button  to “manually” select the photos or folders that contain them on which you want to act.

At this point, press the  Add action button , select the Image item and the Resize item from the menu that appears. Set all the parameters you want to use to resize the photos via the menus below (you can preview the final result on the right) and click the  Convert button .

You can also resize your digital photos so that anything that exceeds the desired resolution is cropped off. To do this, choose the  Resize Canvas option instead of Resize from the Add Action  menu .

By default the program creates a copy of the resized images in the same location as the original files. However, if you want to change this behavior and define a different output location, click on the  Destination  tab at the top of the program window, press the (…)  button located in the Destination section and indicate the path you prefer from there.


Another great tool you can refer to to reduce the size of a photo on Mac is GIMP . In the strange event that you have never heard of it, I inform you that it is a totally free and open source software that includes numerous advanced photo editing tools and allows you to obtain results equal to those that paid software is able to return and professional character (or almost).

To download and launch GIMP on your Mac, go to the program’s website and follow the instructions I gave you in my specific tutorial on what to do .

Once the GIMP window is displayed on the desktop, click on the File menu at the top left, then the Open item present in it and select the image in relation to which you want to act.

Now, to intervene on the resolution, expand the Image menu which is always at the top and select the item Scale image from the latter. In the window that opens, type the new size you want the photo to assume. If you don’t want the width and height of the image to keep their original aspect ratio, click the chain icon . Then select the type of Interpolation you want to use using the appropriate drop-down menu and click on the Scale button .

If you want to resize an image by cropping it, instead, click on the Image menu at the top and select the Surface size item from the latter. In the new window that appears on the screen, type the dimensions of width and height that you want the photo to assume and click on the Resize button to save the changes. You can also preemptively press the Center button  to center the image before resizing and cropping it, while using the X and  Y fields you can set a custom position.

In all cases, to save the edited photo click on the File menu at the top left, select the item Save as from the latter and indicate the location and output format.

If, on the other hand, you want to intervene on the weight of the photo, click on the File menu at the top left, then on the Export as item present in it. In the new window displayed, indicate the folder in which to save the file, specify a name to assign to the image, click on the (+) symbol located next to the wording Select file type and set the file format to be used for saving among those proposed.

Then, click on the Export button and use the options offered to define the image compression level. Remember to enable the option Show preview in image window , in order to visualize its size, then use the  Quality control bar to define the quality of the output files. If you deem it necessary, click on the (+) button corresponding to the Advanced options item to intervene on the encoding options. To save the final result, then, press the Export button .

Other solutions to reduce photo size on Mac

Looking for other third-party resources by which you can reduce the size of a Mac photo? Find them in the list below! I sincerely hope they are able to satisfy you.

  • JPEGmini  – this is a program specially designed to reduce the weight of images in JPG format on Mac, which can be used by simple drag and drop. It’s paid (prices start at $59), but it’s also available as a free trial version.
  • Pixelmator Pro– known photo editing application specific for Apple devices which is extremely powerful, but also very easy to “handle”. It includes many functions, including some to reduce the size of a Mac photo. It is paid (it costs 39.99 euros), but you can try it for free for a limited period.
  • Photoshop– this is the most famous and used Adobe program in the world for photo editing and various graphic creations. It offers advanced tools and functions, also useful for resizing photos, but it is easy to use even by the less experienced. It is paid (it has costs starting from 12.19 euros / month), but you can try it for free for 7 days. For more details, read my guide on how to use Photoshop .

How to reduce photo size on Mac online

If you don’t want or can’t download new programs on your computer, I inform you that it is also possible to reduce the size of a photo on your Mac online , using some special Web services that can be used directly from the browser . If you are interested in this, below you will find those which, in my opinion, are the most efficient in their category.


ILoveIMG is an online service that allows you to resize photos in JPG, PNG, SVG and GIF formats, allowing you to act on the pixels or on the percentage. It’s super easy to use and it’s free. However, limitations are applied regarding the maximum size of the files to be uploaded, which can be circumvented by subscribing to a paid subscription (at a cost of 4 euros / month) which also allows you to unlock extra features.

To use ILoveIMG, visit its home page , click the Select Images button and select the photos on your Mac you wish to edit. Alternatively, you can drag the images directly into the browser window or you can get them from Google Drive and Dropbox  by pressing the relative buttons.

Once the upload is complete, if you want to resize the images in pixels, choose the In pixels option , fill in the Width (px) and Height (px) fields with the dimensions of your interest and select or deselect, according to your needs, the Keep options aspect ratio and Don’t enlarge if original is smaller . If, on the other hand, you need to resize the images by percentage, click on the Percentage item and set the option you prefer.

Finally, click on the Resize images button , then proceed with the download of the modified image by clicking on  Download resized images . You can also decide to save everything on the supported cloud storage services or to share it via link, by clicking on the appropriate buttons.

Do you need to compress photos? In this case, go to this other web page , upload the images, press the Compress images button and download the output files. Et voila!

More solutions to reduce photo size on Mac online

Are you looking for other solutions by which you can reduce the size of a photo on Mac by acting online? I’ll settle you right away! You can find them in the list below. I hope they are able to satisfy you.

  • Img2Go– this is an excellent online service that provides users with various tools for intervening on photos, including changing their size, compressing and upscaling them. Basically it’s free, but it applies various limitations, including that of the maximum file size, which can be circumvented by subscribing to a paid subscription (at a cost of 5.50 euros/month).
  • Photopea– is a very advanced photo editor that works directly from the browser and can be used without the slightest problem even by those who are not experts in image editing. Among the various functions available, there is no shortage of those for resizing photos. It’s free, but has banner ads that can be removed by subscribing to a paid plan (prices start at $9/month).
  • ResizePixel– is an online service specifically designed for resizing photos. It allows you to act by changing the size of the images, compressing and cropping them. It is free and very easy to use.


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