Knowledge Base

Which Image Formats are Compatible with Emails?

Using images and graphics can make your emails stand out. In fact, it is a great way to grab the attention of your subscribers and to convey more in less. Rather than an email cluttered and loaded with words, any reader would definitely enjoy a crisp yet colorful display containing vital information.

However, including images requires some careful planning; the foremost being whether the image format is compatible over email or not.

Let's explore how to pick the perfect images to make a lasting impact: 

Choosing the Correct Image Format

Image file format refers to the compression technique applied to the images in order to store them on your device. Image compression reduces the memory required by the image when it is stored on your computer. It may alter the way the images appear when you zoom in on them.

The compatible image formats that are used in emails include: 

1. JPEG or JPG (Joint Photographic Experts Group)

The JPG/JPEG image format has emerged as a standard for images over email or on the internet. It works rather well for almost all images as it allows nearly 16.8 million shades of colors! 

2. GIF (Graphics Interchange Format)

GIF looks pleasing only if this format is used for images having fewer colors, given that it can handle only 256 different colors. However, this format can display animated content. 

3. PNG (Portable Network Graphics)

While the PNG format is similar to GIF, it can display colors in a more effective manner. There are three types of PNG formats, namely, PNG-8 (allowing 256 colors), PNG-24 (allowing 16.8 million colors), and PNG-32 (allowing 16.8 million colors along with transparency). 

NOTE: PDF, AI, and PSD formats are not used in emails as the display of such images is not consistent across browsers. If an image file is not available in any of the above formats, you could use an image editor or a graphic design software to change the image into the JPG/GIF/PNG format. 

Check the Image File Size

The file size is measured as the amount of data contained in the image with kilobytes (KB) or megabytes (MB) as the metric. Images of size less than 50 KB download quickly over the receiver's browser. However, if the size of your image is more than 50 kB, it would be wise to change the size using an image editor application.

For large file sizes, you can reduce the image dimensions or decrease the resolution, so the images load quickly on the viewers' browser. 

NOTE: If you reduce your image's resolution, you can choose an optimum resolution of 72 dpi (dots per inch), which is suitable for the image to appear clearly on the mail. However, when printed, an image of 72 dpi would appear pixelated and fuzzy. Thus, if the subscriber plans on printing the email, you can attach the PDF version of the mail with the image quality of 300 dpi (or higher). 

Other Useful Tips

  • Images should be saved in the RGB format as some email clients and browsers are not capable of displaying images in the CMYK formats as it is usually used in print media and not on the internet.
  • Avoid using special characters or spaces in the image filename.
  • You may make use of image padding to control the image position. However, you also need to factor in the padding to influence how wide you wish the image to appear.


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