How to Compress an Image?

Optimizing a photo is a crucial step you need to take prior to publishing it on the Internet. Compression plays a key role in image optimization, since it allows you to reduce the size of your visual content dramatically and without a significant loss of quality. The difference between the original photo and the compressed copy tends to be practically unnoticeable to the naked eye. What’s more, this extremely simple process won’t take long. However, to achieve the best results and preserve the superb quality of your visual content, you need to know how to compress an image the right way.

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Why is Image Compression Important?

You’re probably wondering what the purpose of image compression is. Well, here’s the answer.

When you downsize your image by compressing it, you can:

      • Reduce the loading time of your website pages, which means all of your beautiful images will be displayed faster.
      • Free up the memory storage of your phone/computer by almost 80%.
      • Quickly and easily share images via email, social networks, and more.

Most often, the need to compress photos arises when they have to be uploaded onto a website. High-resolution images of a large size will impact your website’s loading speed negatively. In other words, even though your photos will look great, they will take an eternity to load. Researchers have already established that if it takes more than 3 seconds for a webpage to load, visitors will leave and look for what they need elsewhere.

Today, people have a dazzlingly vast choice of products and services, which, naturally, have spoiled them and now, they will simply refuse to spend a lot of time and effort to buy something they want. Thus, it’s your job to optimize your website and make it load with a lighting fast speed. If you don’t provide your customers with great shopping experience, they will go to your competitors.

What will happen if you don't compress images before posting them on your website:

  1. Increase in page load time and drastic drop of the conversion rate. If you fill up your website with high-resolution, high-quality images of a large size, they will take a long time to load; even if visitors have a strong internet connection. As it has already been mentioned, people dislike it when websites don’t load quickly. They will get tired of waiting and leave. As a result, you will have fewer visitors, which will make the conversion rate drop. Subsequently, that will lead to the decrease of your revenue.
  2. Visitors might lose some of their internet traffic. When visiting your website that has a lot of large, high-quality pictures, people might lose a sizeable chunk of their internet traffic without realizing it. That won't make them happy, for sure.

Another point worth noting is that even if you don’t have your own website, you might still need to compress your images. Quite a lot of websites have limits on the size of photos for upload. For example, profile pictures usually have to be of a relatively small size. A website will refuse to upload an image, the size of which won’t comply with their requirements, and prompt you to choose another photo. This issue can also be easily solved with compression of image files.

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How Does Image Compression Work?

Compressing an image means reducing its size in bytes while keeping its quality at an acceptable level. If you don’t zoom in too much, the original and the compressed copy will appear to have the same excellent quality. The important bit of information to know, though, is that different types of compression exist – lossy and lossless – and image formats tend to support one type of compression, but not the other.

If you compress photos correctly, you can easily reduce their size by 70 – 90%.

There are two main ways to compress photos:

      Compression of photos without loss of quality. Lossless compression doesn’t remove any critical data from an image or reduce its quality. The other advantage of this method is that your compressed images could easily be restored to the initial state without any distortion or degradation. The downside, however, is that with lossless compression, the size of your images won’t be dramatically reduced. One of the most popular formats that supports lossless compression is PNG.
      Compression of photos with loss of quality. The way lossy compression works is it removes the less crucial, redundant data permanently. It can greatly reduce the file size, but it can also degrade the quality – that is, if you overly compress your image. With the right amount of lossy compression, the image quality can be well-preserved. Another thing to note is a photo that went through lossy compression cannot be restored to its initial state, since this process is irreversible. JPEG is the most common image format that supports lossy compression.
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Lossy compression relies a lot on the imperfections of the human eye. When you compress JPEG images, the compression algorithm targets similar hues and color transitions. Human eye detects the difference between darkness and brightness much better than the difference between colors. This is why black and white photos can have a lot of depth and details. Whereas, if you get rid of all the bright and dark spots in a photo, you will be left with splotches of color and no sense of dimension. Thus, lossy compression tends to retain the contrast of brightness and darkness, sacrificing similar hues instead.

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Where Can You Compress Photos?

You can compress an image using various online services and software. Even some standard programs that all Windows and Mac computers have allow you to reduce the size of your photos by compressing them. In other words, it’s quite an easy thing to do, and you won’t need any image editing skills.

However, Watermarkly’s online image compressor will simplify this process as much as possible, while also making sure that your images are compressed the right way. There will be no need for you to download or install our app on your computer, search for drivers or plugins. You will get your compressed copies within minutes!

A website or social media platform can automatically compress images of large size, if you decide to publish them online. This may lead to degradation of their quality – your photos might turn blurry and pixelated. If you want your visual works to look good on a website or social media, you’ll have to reduce their size by compressing them in an app that was specifically designed for this purpose.

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How to Compress an Image in Our Image Compressor

Watermarkly works with three popular image formats:

      • JPEG;
      • PNG;
      • GIF.

Most JPEG images can be compressed without significant loss of quality. So do PNG and GIF.

Our image compressor reduces the size of your images by removing redundant information from them.

Our app will do its best to preserve excellent image quality as much as possible and ensure that your compressed photos look just as good as the originals.

Now you will learn how to compress an image:

  1. Go to the “Compress” page on our website.
  2. Upload one or several images by dragging files directly from a folder or click on "Select Images" and choose one of the following options: from your computer, Google Drive, Google Photos, Dropbox. If you want to import images from either of the cloud storages, you will need to grant access to your account first. select images to compress
  3. In the “Settings”, select the quality of your compressed images. select quality of compressed photo

Our app offers three options of compressing an image:

  1. Better Quality. By choosing this option, you will tell Watermarkly to compress an image while prioritizing the preservation of excellent quality.
  2. Smaller Size. If downsizing your photos dramatically is your main goal, you should go for this option.
  3. Specific File Size. This option is ideal if you need to downsize your photos to a certain number of kilobytes and have more control over the final results of image compression.

If you choose the first or second option, you will see the size of your compressed images in bytes only after the process is finished.

When compressing an image, Watermarkly does everything in its power to keep the quality of your compressed photos at the level of the originals yet reduce their size from megabytes to kilobytes.

How to Compress an Image on a Smartphone

If you need to urgently compress photos that are stored on your phone, you won’t have to transfer them to your computer – you can use our app in your mobile browser. Just open our website and go to the Compression page. The mobile version of Watermarkly looks and works exactly like the desktop one. The process is the same – import your photos and choose the option of image compression that suits your needs. Depending on your choice, compressed copies will be saved to your phone’s gallery or one of the cloud storages.

With our online tool, you will be able to compress an image on Mac, Windows or any other operational system. It can also work on a smartphone. No matter if you have an iPhone or a device with Android OS, you can easily compress your photos anywhere you are – as long as you have the Internet access.

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Advantages of our Image Compressor

Our app has a lot of benefits:

  1. You can upload images in three different formats: JPEG, PNG, and GIF– and compress all of them at the same time. You won’t have to process your JPEGs and PNGs separately. The free version of the app allows you to upload a batch of up to 10 images. However, we also offer three paid editions, with either of which you will be able to process dozens of files. You can read more about them on this page.
  2. Watermarkly is a web application that does not need to be installed on a computer. Just open the browser of your choice, go to our website and start compressing your photos. There is no risk of unknowingly downloading a malicious file, no need to waste time installing any software. All features of our image compressor are fully available even in the free version.
  3. You can compress an image in a few clicks. Our app works not only efficiently but also unbelievably quickly. You will get your compressed images in a matter of minutes – if not less!
  4. Your data and files are safe with us. Your images will be compressed right in your browser. Thus, they will never get stored on our servers. We won’t collect any of your personal data, either.
  5. Our website has more to offer than just compressing an image. With Watermarkly, you can easily add watermarks to pictures, crop photos into a circle or rectangle as well as pick one of the popular aspect ratios, resize the picture, or add a logo.
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You don’t need to be a professional image editor to use Watermarkly, because each of our online tools was designed to be uncomplicated and easy-to-master. All the step-by-step instructions that we provide are unbelievably simple to follow.

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JPEG, PNG, GIF. When Each Format Should Be Used?

There are three formats that are widely spread:


The vast majority of images you see on the Internet are JPEGs, which isn’t surprising since this format is perfect for photos that have a lot of details and colors. You can apply a strong compression to JPEG images to dramatically downsize them, but it may degrade their quality – it’s a lossy format, so you have to be careful. With the right amount of compression, however, you can achieve spectacular results. What you also need to know is that JPEG doesn’t support transparency and isn’t suitable for images that have a small amount of color data; for example, screenshots. Even if you’re not going to compress them, it’s better to save screenshots as PNG.


This format handles sharp edges and less subtle color transitions much better than JPEG, which is why it’s most commonly used for logos, icons, and images with a lot of text. This format is very versatile since it supports transparency and lossless compression, which means when PNG files are compressed, no data is lost. However, compressed PNGs always have a bigger size in bytes than compressed JPEGs. Also, this format isn’t suitable for highly-detailed images liked photographs.


This format also supports lossless compression, but, at the same time, GIFs tend to be of more manageable size than PNGs. GIF can covert images into animations, therefore it is usually used to create files with animation. It has some downsides as well: it doesn't support blended boarders or shadows, offers a rather limited choice of colors and doesn't convey dimensions all that well. Moreover, it is a bit challenging to compress GIFs, because the result might look a bit pixelated and, generally, not very good.

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Answers to Frequently Asked Questions

We have prepared several answers to the most popular questions on how to compress an image and hope that you will find them useful. However, if something remains unclear to you, you can contact our support service.

How to compress an image in jpeg format?

You can compress JPEG images in our online app. The process is extremely simple. You need to import your photos, choose one of three options – Best Quality, Smaller Size, Specific File Size – and click on “Compress Images”. That’s it! No matter what option you’ll choose, our Image Compressor will keep the quality of your compressed files as close to the original as possible.

Why might I need to compress photos?

Usually, it is necessary to downsize images before posting them on your website, because large-sized, high-quality images might dramatically slow down the loading speed of your webpages. Also, some websites and social networks have a limit on the size of images that can be uploaded to their platforms. So, if you want your photo to be small enough to be uploaded, yet still look great, you will need to compress it. This process won’t take long if you use Watermarkly.

How to compress an image without losing quality?

This is pretty much impossible, if you want to compress a file in lossy format, like JPEG. In lossy compression, removal of some redundant data and insignificant loss of quality is inevitable. However, this isn’t something that you should be worried about. If compression isn’t strong, you won’t see any difference between the original photo and the compressed copy. One thing to keep in mind, though, is if you want to achieve the best results, you will need to use an app that allows you to preserve the best quality when compressing images. Fortunately, Watermarkly has this feature.

How much can JPEG be compressed?

Generally speaking, if you want your compressed images to look good, you should avoid really strong compression. Of course, it is possible to reduce the size of your JPEG to 5 percent of its original, but it will lead to a dramatic, evident degradation of quality. Don’t forget that when lossy compression occurs, some data gets removed. Since compressed JPEGs contain less information than the original, some elements like level of sharpness or subtle color transitions might disappear.

Do I need to compress photos to send them by email?

Usually, yes. You do. Most mail services have a limit on the size of attachments that you can send – it's somewhere around 25 MB per letter. To send a bunch of photos that collectively exceed this limit, you will need to compress them first. With our app, you can easily do this in a matter of minutes.

How to compress an image on iPhone?

Watermarkly will come to your rescue here as well. You won’t have to download any mobile apps to compress your photos on iPhone or Android. Our website has a great mobile version, which means you can use our online tools in your mobile browser. The process of compressing images is the same as in the desktop version – upload your photos, choose the level of compression that you want, and download your compressed copies.

Why do I need to compress photos if I don't have a website?

For a number of reasons. When you compress photos, you downsize them from megabytes to kilobytes, which will allow you to send them over an email or free up a lot of memory space on your device. You will also be able to upload your compressed photos to various social media platforms without worrying about size limits.

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Compress Photos in a Few Minutes with Watermarkly

Now, you know why you might need to compress an image and how to do it easily on our website. If you need to optimize your photos for the web quickly, open our Image Compressor and get to work. All the tools and features are available for free and online. If you want to process more than 10 photos in one go and get rid of a few other limitations in working with images on our website, consider purchasing one of our three paid editions.

With Watermarkly, you will get compressed images that are of smaller size yet have outstanding quality. You won’t have to waste your precious time installing any software on your computer or downloading an app to your phone. With us, optimizing your images for web will be effortless, efficient and quick.