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3 Easy Ways to Compress Image in PDF

Sometimes the images that are on the PDF document you are working on can be very large. This can make it difficult to effectively share the PDF document via certain channels. One of the ways to mitigate this problem is to compress images in PDF.

The process of compressing PDF images can be very simple if you choose the right PDF editor and follow the right processes. In this guide, we look at this process in greater detail and the best ways to do it.

What is Image Compression?

Image compression is a process that is employed to compress pixel data and in so doing effectively reduce the size of the image. For example, if you are going to store a 1020x768 image without compressing it, it would take up about 2.3 MB of data. Chances are, you don't have just one image, increasing the chances of having a very large document that will be almost impossible to share.

The method of compression that you choose, or even if you compress the image or not, will depend on the type of image that you have. For instance, JPEGs do not retain 100% of the information and work great for photos, but PNGs are lossless formats that work great for screenshots. JPEGs, therefore, tend to compress better than PNGs which carry a lot of information.

There are various ways to compress images and the one you choose will depend on the kind of image you have on your PDF document.  If the images are in PNG or GIF format, then you want to choose a compression method that will not affect the quality of the image. Choosing a lossless compression method is useful for documents with GIFs as they restore the data after the file is uncompressed. During compression, the long strings of code are changed into shorter codes but the file remains largely unchanged.

Why You Need to Compress Images in PDF 

Compressing images in PDF is not just a useful solution when sending large PDF files via email, but can also be beneficial in several other ways, including;

1. Compatibility

Perhaps the biggest reason to compress images in a PDF is to make it easy to share the file. This is especially true if you choose to use email as your medium to share files since email is often limited in terms of disk space. The PDF with compressed images will not just be compatible with email, allowing you to attach it easily, but it will also be easier to print and upload to websites.

2. Save Storage Space

Reducing the size of the image will save you storage space as the size of the PDF document will also be significantly reduced. This becomes more important when you have a lot of PDF documents with large images. More room on your computer will allow you more room for more data.

3. Faster Document Processing Speeds

A smaller PDF means faster document processing speeds.  You will send the PDF files much faster and download any documents sent to you more easily. Compression makes this possible because it reduces the amount of time it takes to download and send a file.

4. Reduced Cost

Spending less time on document processing can have a hugely positive effect on the overall cost to the company. Smaller files mean you spend less time on the company network and ensure the optimization of the disk space, allowing the company to store more documents at a fraction of the cost.

5. Easier Batch Processing

Compression makes it very easy to process multiple documents at the same time. Using compression tools like WinRAR can allow you to combine numerous documents at the same time and send them in one tiny convenient bundle, rather than send one huge file at a time.

6. Easier Backups

Creating a backup of the data on any of the devices you own is a common practice that can be instrumental in protecting the data from loss. And file compression is at the center of any backup process. File compression makes it easy for you to transfer the backup to another device and store numerous backups without worrying too much about storage space.

Why UPDF is the Best Tool for You

If you work with PDF documents regularly, then you know that some of the best PDF tools in the market can be quite expensive. But now there is a revolutionary PDF tool that gives you all the features you would expect on some of these expensive alternatives but at a lower cost to you.

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UPDF can help you manage your PDF documents in various ways, including:

  • It offers the best PDF reading experience, allowing you to read and annotate any PDF document with ease.
  • It is also one of the best ways to edit a PDF document. You can very easily edit the text including the font and size. It also comes with an image editor, allowing you to replace, resize, reposition, crop, or delete any images within the document.
  • UPDF can also be a great way to manage the pages on a PDF document, allowing you to rotate, reorder, replace, extract, delete and even add new pages to any section of the document.
  • UPDF offers annotation functions that allow highlighting, underlining, adding stamps, including stickers, and signing documents. To manage documents and provide feedback, you can use the commenting function of UPDF.
  • If you want to protect the PDF document, UPDF can be used to secure the documents with the help of passwords. These passwords can range from open passwords to permission passwords, where you can specify the restriction that you are to put on a document.
  • The OCR feature of UPDF is one of the most elaborate tools in the PDF editor. It provides two different document types to perform OCR on. With the support of 38 languages, performing OCR with UPDF is easy.

Way 1: How to Compress Image in PDF by Cropping

To manage the size of a PDF document, you must manage the media it contains. The best way to manage the size is to reduce the image you used in the PDF document.

For this, you have two different approaches that you can use to reduce the image size. Firstly, UPDF provides the option of "Crop", which can easily decrease the size of the image. If the image is too large, you can remove the extra spaces by cropping them out.

Step 1. Enter into the Editing Mode

First of all, you should enter the editing mode by clicking the "Edit PDF" icon displayed on the left toolbar.

Step 2. Crop the Image to Reduce the Size

Double click the select the image, and then you will see that there is a "Crop Image" icon on the floating toolbar that appears above or below the image. Click on it.

Then you can either drag the purple dashed box to begin cropping, or you can enter the width and height. Your image will become smaller.

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Way 2. How to Compress Image in PDF by Resizing

Additionally, UPDF also offers the option of resizing the image size with the "Resize" option. The resizing function allows you to reduce the image size and easily manage your document.

It provides the opportunity of managing the images of the PDF under such defined settings. The tool's longevity makes it look straightforward and elegant in all cases.

  • The same with the first way, you need to enter into the edit mode first.
  • Click to select the image you want to resize and make it smaller.
  • Drag the purple box to resize it as per your requirement.

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Way 3. How to Compress Image-Based PDF Effectively

When you deal with scanned PDF or image-based PDF documents, you will find that they have a really big file size. This is the problem with scanned documents and they will take up too much of your storage.

Luckily, UPDF provides an OCR feature to help you make the image-based PDFs much smaller than the original files. Follow the steps:

Step 1. Click the OCR Button

After you open your PDF document, you will find a button about OCR displayed on the right side of the toolbar. When your cursor hovers on it, it displays "Recognize Text with OCR".

Step 2. Perform OCR to Get a Smaller Sizes PDF

In the new window, you will find the option "Searchable PDF". Then you need to choose the layout, the document language, the image resolution, and the page range.

From here, if you select the layout as "Text and pictures only", the output PDF file will have a relatively smaller size. And setting the image resolution also helps you reduce the file size.

Finally, click the "Perform OCR" button and within a few seconds, you will get a PDF file with a smaller size. What's more? The texts in it become searchable and editable.

Alternatively, you can compress PDF file size by optimizing PDF file with UPDF. To do this, you can tap on "Save as Other" > "Reduce File Size..."

Then you can select any of the document qualities to compress the PDF file size. Once done, click the "Save As" button.

These are all the steps you need for compressing PDF files. Only 2 steps to solve your problem because of user-friendly interface of UPDF.


The developers of this very useful PDF tool are constantly improving its function to make it easier to use and also to introduce new features. Upcoming features include PDF forms, digital signatures, and so on.

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