If you’re working with an image that is too large to upload to a website, social media platform, or simply store on your computer, you can reduce its size, even to a precise number of kilobytes. So now, without any further ado, let’s cover online ways of reducing the KB size of a photo as well as options for Windows, Mac, and Linux.

4K Image Compressor (Windows, Mac, Ubuntu)

4K Image Compressor is a desktop application compatible with Windows, macOS, and Linux devices. It can easily optimise JPEG, HEIC, WEBP, PNG and PDF files as well as convert images to other photo formats. In addition to automatic compression, 4K Image Compressor can reduce a photo’s size to a certain percentage or the number of MB, KB and even bytes. Apart from single image compression, the tool is capable of optimising photos in bulk.

But let’s see how it works if you simply need to reduce the KB size of a photo:

1. Launch 4K Image Compressor.

2. Choose the image format. 4K Image Compressor supports JPEG, PNG, HEIC, and WEBP.

3. In the Optimization tab, choose File Size.

3. Select kilobytes (KB).

4. Enter the desired number in the size field.

5. Click the Compress button located in the middle of the application window.

6. In the opened window, select the image for compression and click Open.

Your JPEG file will be immediately uploaded and compressed by the specified percentage.

Hover the cursor over the compressed image preview and click the folder icon to find the file on your computer.

Paint (Windows)

If you prefer the native ways of compressing on Windows, you can use old but gold Paint. Here’s how to reduce the KB size of an image with this software that is installed on your Windows computer by default:

1. Tap the Windows Start menu.

2. Enter Paint and click on it once the system finds it.

3. Open your image in Paint by clicking on File -> Open to open a file browser.

4. Choose the image you want to reduce the size of.

5. Select Open in the lower-right corner of the file browser.

6. Click Resize.

7. Next to the Maintain aspect ratio, find the checkbox and click on it.

8. Then, use of these options: Either check the percentage box and type a number percentage in Vertical or Horizontal. Or check the Pixels box and type a pixel number in Vertical or Horizontal.

9. Tap OK.

10. Save your file in any format you need.

As you can see, this option is a bit thicker than using 4K Image Compressor.

Reduce the KB Size of a Photo with Preview (Mac)

Just like Windows users, Mac fans also have a native built-in way to compress images to a certain amount of kilobytes if they don’t want to install any third-party software. And that’s Preview, a default image viewer and basic editor. Here’s how to use it:

1. Open any image by clicking on it twice. It’s likely that the image will automatically open in Preview. If it doesn’t, click on the image and choose Open with -> Preview.

2. Click Tools -> Adjust Size.

3. Choose the measurement unit: pixels, percentage, inches, cm, and more.

4. Type a number in the Width or Height boxes, but make sure the option Scale proportionally is checked so that your image isn’t distorted after you resize it. Or choose any option from the Fit into box.

5. Press OK -> File.

6. Save the image you’ve just resized.

How to Reduce the KB Size of an Image Online

One of the online tools you can use to reduce the KB size of any picture is Duplichecker. It works pretty easily: you just need to upload an image (or drag and drop it), set the desired size of KB in Quality, and choose the compression type.

Other similar online tools that work basically the same are ResizePixel, SmallSEOTools, Pi7 Image Tool, and Simple Image Resizer.