Which image format is best for email newsletters: JPEG, GIF or PNG?

JPG / GIF / PNGThere are many different image file formats to choose from for your pictures - BMP, TIFF, EPS, JPEG, PNG and GIF. But which format is best for email / electronic newsletters? In this article, we try to give you an answer to this question.
We can start with excluding file formats such as BMP, TIFF and EPS. They are neither suitable for web nor email. Many web browsers and email clients cannot even display them. The remaining image file formats, JPEG, GIF and PNG, are well adapted for the Internet, and below we provide you with a brief description about the differences between these three image file formats.
JPEG is good at handling photosJPEG (sometimes also written as JPG) is an acronym for Joint Photographic Experts Group. It is an image file format optimized for photographs. A JPEG image can contain up to 16.8 million colors so the number of shades of one color is extremely large. That is why JPEG is so good at handling photographs. JPEG has also a very efficient compression technique that combines high compression degree with minimal quality loss. However, there is a certain limit for JPEG's image compression, and that is when the picture quality drop becomes visible. That can happen if you use a very high compression degree. The reason to this is that the JPEG compression method removes information from the image (so called lossy compression). If you compress the image a lot, the quality loss becomes visible to the naked eye.
JPEG in general is very good at handling photographs, but it is much less successful at handling text, drawings (with straight lines) and similar. Text stored in JPEG may become slightly blurry and it is therefore not recommended to use JPEG for showing text. Instead, use the GIF or PNG format for this purpose. Below you can see how different the quality can be between JPEG and the two other image formats; GIF and PNG:
This image is saved as a GIF image This image is saved in the GIF format.
This image is saved as a PNG image This image is saved in the PNG format.
This image is saved as a JPEG image This image is saved in the JPEG format.
How blurry text stored in JPEG becomes, depends on the compression degree. The less you compress the picture, the sharper the text will get. However, this also means that the image file size remain bigger with less compression.
Advantages Disadvantages
Suitable for photographs Applies lossy compression with image quality drop
Supports many different color shades Not suitable for images with text
High degree of image compression available Not suitable for drawings and illustrations
n  GIF
GIF is an acronym for Graphics Interchange Format. An image of the GIF format can contain up to 256 different colors. This means that GIF is not a good a choice for photographs as the number of available colors is very low. On the other hand, GIF provides a good option for handling text and illustrations. To begin with, less color tones enhance image contrast (with stronger image outlines). Another plus is that GIF compression technique does not remove any information from the image so the picture quality remains unchanged, even if the file size has been reduced. For images containing text, always consider choosing GIF format before JPEG. Alternatively, PNG format can be used as it also handles text very well and it is therefore suitable for saving images with text as well.
Another advantage with GIF is that parts of the image can be made transparent. That is not possible with JPEG. A picture that is (partially) transparent can for instance be placed over another image with the effect that the image beneath is partially visible through the image. This can be useful for example when placing text or graphic objects over photographs or other images.
A further advantage with GIF is that the format can be used to create animated images. This is fairly common on websites, and it is also sometimes used for email, although not all email clients support it. However, web-based email clients are usually able to display an animated GIF without problems.
Advantages Disadvantages
Suitable for text Not suitable for photographs
Enables transparency Only 256 colors support
Handles animated images Inefficient compression
n  PNG
PNG is an acronym for Portable Network Graphics. It is a newer image format compared to JPEG and GIF. PNG was partly designed to replace GIF and as such, it comes with new features. There are three types of PNG image format: PNG-8 which supports up to 256 colors, PNG-24 which can contain up to 16.8 million colors and PNG-32 that can handle up to 16.8 million colors and has an advanced functionality for transparency.PNG handles transparency very well
PNG supports transparency just like GIF, meaning selected image areas (or whole images) can be made transparent. Additionally, PNG even allows you to specify the degree of transparency in percents (so called alpha compositing). That means that you can control to which grade the background image will be showing through. It also gives you the possibility to merge PNG images together with their background in a far better way compared to GIF. This can be best seen when circular or irregular shaped images are placed over other pictures. The transparency degree control also allows you to create realistic shadow effects by enabling interaction between foreground and background images in a way that is not possible with GIF.
PNG is quite good at dealing with photographs as well. In fact, it is much better than GIF and generally as good as JPEG. PNG uses a different compression method than JPEG that does not cause any information or image quality loss (so called lossless compression). The downside of the PNG compression technique is that you cannot shrink the file size as much as with JPEG. This means that the image file size of large pictures can be quite big. If you need to significantly reduce the image file size, it is preferable to use the JPEG format for that.
Additional PNG disadvantage is that some older web browsers and email clients do not support the format as it is quite new compared to GIF and JPEG. However, all new web browsers and email clients fully support the PNG file format.
Advantages Disadvantages
Suitable for logos and text No support for animated images
Advanced transparency control File size of large detailed images can be big
Supports many color shades Not supported by all web browsers and email clients
What image format is the best?
There is no obvious answer to this question as it all depends on the context. In general, the JPEG format is suitable for displaying photographs with minimal file size requirement. The GIF format is suitable when using text in images, for viewing illustrations, showing animated images and images with simple transparency. The PNG format is suitable when there is a need for more advanced transparency control and for handling logos and detailed colorful icons.

More information
Read also these informative articles on Litmus website to get more details and facts:
PNG, GIF, or JPEG? Which is the Best Image Format for Email?
A Guide to Animated GIFs in Email
See also

See also this article on our website that gives you information about where you can find free and cheap images:
Free images for your newsletter and blog
SamLogic Image ResizerConverting between different image formats

It is not always the case that you have an image in a format that is needed or desired. However, if you use our newsletter marketing software MultiMailer, you have an excellent image converter included the software: Image Resizer. Image Resizer allows you to easily convert images between different formats, and to change size and resolution of your images.
Learn more about Image Resizer here
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Article written by: Mika Larramo Swedish