4K Image Compressor Review: a FREE Tool to Shatter the Limits of Image Compression

In the age of digital photography, pictures have become an integral part of our lives. However, with the continuous capture of images comes a big headache: storage. High-resolution images take up a lot of hard drive space, leaving little to no room for other important files.

That is where image compression tools enter the scene. Using these helpful applications, it is quite simple to reduce the size of your images without sacrificing a lot of quality. Such an application is 4K Image Compressor, a free application that promises to shed pounds from your images.

We’re going to take a deeper look into 4K Image Compressor in this review. We will dig deeper into its features, benefits, and limitations to determine whether it’s the right tool for your needs.

4K Image Compressor Review: What is it?

4K Image Compressor is a free, cross-platform application (Windows, macOS, Linux(Ubuntu))that helps you reduce the size of your images. It supports a variety of image formats, including JPEG, PNG, HEIC, WEBP, and PDF and even more.

The app uses two main compression methods: lossless and lossy. Lossless compression reduces the file size of an image without sacrificing any quality. However, the amount of compression you can achieve with lossless compression is usually limited.

Lossy compression, on the other hand, can achieve much higher compression ratios. However, it does this by discarding some of the image data. This can result in a slight loss of quality, but in most cases, the difference will be imperceptible to the naked eye.

You can check the comparison: 

The original photo can be found here.

  • Resolution: 4368×2912
  • Format: JPG
  • Size: 3.7MB
  • Preset: Medium

And, the output is 927 KB. How do you think it works?

4K Image Compressor Key Features

During my 4K Image Compressor review, I found it to be over a powerful tool that goes beyond simple shrinking, it offers a comprehensive set of features to optimize your images for any situation.

Lossless Compression

4K Image Compressor’s lossless compression is a method for shrinking image file sizes. But the best part? The actual image data remains completely intact, meaning you won’t see any difference in quality compared to the original image.

From what I can see, it saves you 10% to 20% space in lossless mode.

Compression Presets

Do you ever feel overwhelmed by all those compression settings? You’re not alone! I understand that finding the perfect balance between image size and quality can be tricky. But in 4K Image Compressor, you have the key to effortless image optimization in its compression setting presets from Soft to Hard.

  • Soft: A gentle preset. Ideal for situations where preserving image quality is top priority. It reduces file size subtly, making it perfect for photos you want to retain the most detail.
  • Medium: A great balance between size reduction and image quality. It’s a fantastic choice for everyday use, shrinking your files while maintaining a crisp and clear look.
  • Hard: If minimizing file size is your ultimate goal, the Hard preset is your champion. It achieves the most significant reduction but keep in mind, there may be a slight decrease in image quality at higher compression levels.

Manual or Preset? The Choice is Yours!

For those image editing ninjas who prefer a hands-on approach, the manual adjustment option remains available. However, for anyone who wants a fast and effective way to optimize their images, the presets are easier ways.

Custom Sizing

With 4K Image Compressor, you have the freedom to specify the Optimization by File Size. For those times when you have a specific file size goal in mind, 4K Image Compressor has you covered. Simply specify the target size in megabytes (MB) or kilobytes (KB), and 4K Image Compressor will work its magic to reduce the image while staying within your designated limit.

You can also choose to reduce the size of your PNG, JPEG, and WEBP images by a specific percentage, which I think is the best way to achieve the desired balance between file size and image quality.


Ever compressed an image and wondered, “Did it actually work?” Well, wonder no more! Since version 1.4, 4K Image Compressor boasts a revolutionary new feature: Post-View Functionality.

With post view, you can directly compare your original image with the compressed version – all within the app! Simply right-click on the image preview after compression, and unleash the power of comparison with Split, Side-by-Side, or Slider Comparison.

4K Image Compressor Review: Post View

Slim Down Your PDFs

My PDF files are usually very LARGE. How about yours? Although named as an image compressor, it can cleverly identify and remove redundant data within your PDFs.

Using this feature is a breeze. Simply head over to the “Optimization” section of the menu bar and select “Auto.” Add your PDF and 4K Image Compressor will automatically compress your PDF files.

Troubleshotting: Suboptimal result. Try using different compression settings

I notice, in some cases, using lossless compression in 4K Image Compressor might actually result in a larger file size, especially for on HEIC files.

HEIC (High-Efficiency Image Container) is a relatively new image format known for its ability to achieve excellent compression with minimal quality loss. So, when you use lossless compression on an HEIC file, 4K Image Compressor tries to further optimize the file by identifying and removing redundancies within the existing HEIC data structure. However, sometimes, the HEIC file might already be highly optimized due to its inherent compression techniques. In these cases, there might not be much room for further lossless optimization using 4K Image Compressor’s algorithms.

Since lossless compression might not be the most effective for pre-compressed HEIC files, consider testing the “Hard” or “Medium” lossy compression settings in 4K Image Compressor. These settings offer a good balance between file size reduction and minimal quality impact. Or, you can simply leave the HEIC files untouched. HEIC itself is a very efficient format.

Pros & Cons

In this part of my 4K Image Compressor review, let’s take a look at the pros and cons before you download it for trying.


  • Lossless and lossy compression
  • Batch compression
  • Image resizing: Resize your images to specific dimensions for social media or other purposes.
  • Multiple output formats or keep the source format
  • Easy to use interface


  • Only 20 compressions for the free version
  • Limited advanced option

Conclusion-Is 4K Image Compressor Right for You?

4K Image Compressor is a valuable tool for anyone who needs to reduce the size of their images. It’s easy to use, effective, and free. If you’re looking for a simple way to save storage space and improve your website’s performance, 4K Image Compressor is a great option.

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