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Which image format for making smaller file size?

Which Image Format for Making Smaller File Size?

In the event that your website has plenty of image data, reducing their file size brings you a huge benefit in the website’s speed optimizing. This task improves not only user experience on your site, but also your site ranking on SERPs.

There are a dozen ways to reduce the file size of an image. One of them, which is the simplest, is choosing a suitable file format for your images. Each image format has its unique features which you should consider to ensure that your image is good at both quality and size.

Let’s see which image format fits your needs.

What is Image Format?

Every file saved in a computer is encoded following the stipulation by file format. The name of the file format stands right after the dot (.) in the file name. It’s also called the name extension. Image files also has name extension such as .gif, .png, .tiff, .jpg, etc. They show which type of image file format.

Choosing a format for your image is the same as choosing how the data of the image is encoded. Then, it affects the image file size.

It depends on your settings on your computer, the information about file format maybe prominently display beside the file name or not. In case it doesn’t display, just hover your mouse on the file name, brief information about the file will show.

The selected image has the file format is JPG

The selected image has the file format is JPG

In another case, if you want to know the file format in bulk, there are two ways as below:

Method 1: Show the Column about the Type of File Format

In the folder where stores your images, take a right-click in a blank place, then choose View > Details. A column named Type will be shown.

Show the column about the type of file format

Show the column about the type of file format

Method 2: Show the File Name Extensions

In the window of File Explorer, go to the View menu, tick the File name extensions box. Name extensions of all the files in your computer will display immediately. They show you what the format of each file is.

Show the file name extensions

Show the file name extensions

You should check the file format of your image in advance and change it to be the suitable one before uploading it.

Common Types of File Format and Their Features

Although there are many types of image formats, you should consider the three most common types as the following for your daily application.


JPEG (or JPG) stands for Joint Photographic Experts Group. This is the most common type because it makes the smaller capacity for the image. So, it’s faster in uploading, downloading, or loading JPEG images on the internet. Moreover, the post or page which includes JPEG images on your site will be load fast. That improves your website speed significantly.

However, pixels will be compressed in the encoding process of the JPEG file. Which one is too small will be skipped. That’s why JPEG images look less colored and sharped than the origin.

Furthermore, your image will be compressed one more time and lost more pixels whenever you edit or save it. This causes quality-reducing for your image. This is “lossy compression” - a feature of data losing from JPEG. It also is the most prominent disadvantage of this type.

So, if you have any intention to store your image in the long-term, JPEG (or JPG) is not an ideal option for you. Otherwise, JPEG (JPG) is the best choice for other needs because of its low-capacity.


PNG stands for Portable Network Graphics. This type of format keeps the data intact and does not affect the image quality even when you save or edit it many times.

Because of that, your image is sharply and colorful as the origin no matter what you edited or saved it many times. Along with that, the file size of the PNG image will be higher than the others. It’s opposite to JPEG (JPG), right?

So, if you obviously need a high-quality image, you should choose PNG.


GIF stands for Graphic Interface Format. It usually is used for animation image or video. Using video format for animation makes the file size larger or difficult to publish. For this reason, GIF is more and more popular in recent years.

The file size of GIF is much smaller than video type but it is true for animation only. People rarely use GIF for static images. GIF has a color panel with a maximum of 256 colors so the image color is less vivid than JPED or PNG. Sometimes, it may be pixelated or distorted.

That’s why you should use GIF for animation only.

IF image has low-quality

GIF image has low-quality

How to Change the Image Format

It’s somewhat easy to change image format. We may use one of the most basic editors to save or export files in another type as you want.

Now I change my image from PNG to JPG by Paint. Open image by Paint then goes to File > Save as > JPEG pictures. Press the Save button in the last step to save your file.

Change image format using Paint

Change image format using Paint

In results, my image reduces the size from 379 KB to 176 KB.

The image file size is reduced when we change it from PNG to JPG

The image file size is reduced when we change it from PNG to JPG

Final Words

You see, changing the image format helps you reduce the image file size a lot. In my case, I saved 53%. With this simple action, you can save the storage on your server as well as speed up your site significantly.

However, if you pay attention to speed up your site only, JPEG and JPG are the most ideal option. Otherwise, if you are to heed image quality, PNG is on top. Hope you have a good choice for your images!

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