Bitmap and GIF were among the first image formats to be developed. JPEG, EXiF, WebP, and Heif were added over time. Here are the differences
It’s easy to say image. A little more difficult is to understand the format through which a photo is saved. But also a preview of a document, a screenshot or a graphic. Let’s take a look at the most popular image formats. From the classic PNG and JPEG to the new HEIF.
Each image format has its own characteristics and peculiarities and is used for a certain purpose. Some of them were born in the early 90s and have survived until today, while others were created with the arrival of the new millennium. The JPEG format is certainly the most famous, but it is not certain that it will give way to some other format that will be launched in the next few years.
BMP
Let’s start with the format that for reasons of “age” and use is the progenitor of the various image formats. We are talking about the bitmap, or more simply BMP. It is a format born in the 90s exclusively for Windows operating systems. It has an enormous flaw for the times: it cannot compress images: the photo is broken down into a large matrix of pixels and each “dot” is represented by 8 or more bits (depending on the quality you choose for storage). This means that a photo saved in this format takes up a lot of space. Unlike other formats, it has a very fast writing time to the disk, but despite this, it is not widely used nowadays.
JPEG
Acronym for Joint Photographic Expert Group and also known by the abbreviation JPG), it is one of the most widely used image formats, although its fortunes are waning. It owes its success to the compression algorithm used (lossy algorithm in technical jargon) that allows you to get good quality images (if not very good) and small file sizes. This makes it particularly suitable for the web, but also for saving images and photos of any kind on the hard disk. The algorithm, in particular, eliminates certain details that the human eye can’t pick up. The JPEG format, for example, “plays” on color nuances, eliminating details and flattening, consequently, the color rendering (JPEGs have a depth of 32 bits, 8 for red, 8 for blue and 8 for green). This results in images with a color rendition very close to the real thing, but with a low impact on the hard disk.
GIF
Acronym for Graphic Interchange Format, it recently celebrated its 30th anniversary, but thanks to Facebook, other social networks and instant messaging apps it is experiencing a second youth. Unlike JPEG, this image format guarantees a color depth of only 8 bits: the file size is extremely limited, but the quality suffers considerably. What may appear to be a weakness, however, is also the strength of the GIF format: creating small, short movies (GIF animations) is extremely simple.
PNG
Designed to be the heir to GIF, Portable Network Graphic ended up “stealing space” from JPEG. Thanks to the use of a lossless compression algorithm (unlike JPEG’s lossy algorithm, it avoids the loss of details and color nuances) and the 48-bit color depth, it allows you to create images with excellent color rendition and reduced size.
TIFF
Acronym for Tagged Image File Format, it is one of the oldest image file formats in circulation (dating back to 1992) and, over the years, has lost most of the functions for which it was born. Initially, in fact, it was intended to be used as a format for the compression of bitmap images; today, however, it is mainly used in the world of professional photography and computer graphics, since it allows the transfer of a lot of information regarding printing parameters between computer and printer. It is also used because of its ability to provide a 32-bit depth for each color channel and the use of multiple color spaces (RGB, CMYK, and others).
WEBP
WebP is an open-source image format developed by Google. At the moment it is not widely used (it is only compatible with Chrome and Opera, while Telegram is the only messaging app that fully supports it), although it provides a good balance between visual quality and file size. It is, therefore, a “modern” image file format, designed and built for the web and to optimize online image uploading.
HEIF
The abbreviation for High Efficiency Image Format, it is Apple’s answer to Google’s WebP format. As the name implies, it guarantees great compression (according to the Cupertino company, it saves up to 50% of hard disk space) combined with good image quality. Introduced during the WorldWide Developer Conference 2017, it should be adopted starting in the fall, when the stable and final version of iOS 11 will be released.
Exif
More than a real image file format, it is an “informational” file format related to the various JPEGs and TIFFs. Used in photography, it allows digital cameras to provide photographic files with a range of information useful in post-production and printing. This information is collected in the form of metadata tags (such as dates and times, the settings and settings under which the photo was taken, a thumbnail and copyright information) to be used at the photographer’s convenience.