GIF format
Acronym for Graphics Interchange Format according to AbbreviationFinder, GIF is another very popular format on the internet. It was created by CompuServe in 1987 and, like JPEG, it generates small file sizes, however, its use is not very common in photographs, since it is capable of working with only 256 colors (8 bits). For this reason, its use is very frequent with icons, illustrations or any type of image that does not require many colors.
There is, however, a feature that makes the GIF format known to the present day: thanks to a revision carried out in 1989, the standard now has the ability to support animations. In other words, GIF now allows the insertion of a sequence of images in a single file. Thus, when a GIF in this condition is displayed, each of the inserted images is shown following an order, giving the user the sensation of movement.
The GIF format has yet another differential: it is capable of allowing an effect known as a transparent background. This means that a GIF file can have areas of the image that assimilate the color of the location where it is being displayed, as if it were, in fact, a transparency. For example: if a GIF image is being displayed on a web page with a green background, the “transparent” areas of the file will be shown in that same color.
GIF also uses compression, but this does not cause loss of quality, even if the image is saved several times. Here, there is a curiosity: the most common compression algorithm of GIF is Lempel-Ziv-Welch (LZW), whose patent belonged to Unisys. Apparently, CompuServe didn’t know that. As a consequence, in 1995, Unisys started to charge companies responsible for image editing programs for the use of the algorithm in question. The patent expired in 2003, making collection no longer allowed.
The extension of files in GIF format is.gif. For example: wholevehicles.gif.
PNG format
The PNG format, which stands for Portable Network Graphics, is one of the most recent standards, with its first specification having appeared in 1996. Its development was motivated, in part, by the existing patent restriction in the GIF format, as explained in the previous topic.
PNG therefore brings together the characteristics that made GIF so well accepted: animation, transparent background and compression without loss of quality, even with constant file saves. However, it has a great differential: it supports millions of colors, not just 256, making it a great option for photos.
In the aspect of animation, PNG, by itself, does not have such capacity. What happens is that there is a variation called APNG (Animated Portable Network Graphics) that makes this feature possible. The layout is the same as the GIF standard: a sequence of images inserted in a single file. In this case, the first image is a “normal” PNG file, which is displayed in situations where, for some reason, the animation cannot be performed. There is also a variation called MNG (Multiple-image Network Graphics) that serves the same purpose.
PNG images have a.png extension, even in animation variations, although in the latter case, names with.mng and.apng can also be used.
PNG is a free format, created from the beginning to be used in any application without the need for license payments or the like. Its use is supported by the W3C.
Note that the JPEG image has acceptable quality for a simple observation, but if you look closely, you will notice that the PNG image shows details more clearly. That’s because the first one went through a compression process that reduced its size well, but compromised its quality a little. The second figure, in PNG, also went through compression, but did not lose quality.
As the original image is rich in color, it lost a lot of quality when it was converted to GIF, making it clear that the format is not suitable for photos like this
What about the WebP format?
You may hear a lot about WebP. Or not. It is an image format presented by Google in October 2010 that proposes to allow the generation of files with reduced size and, at the same time, good image quality.
For this, the standard uses a compression scheme that makes the loss of quality as small as possible for human eyes. According to Google, this method is capable of generating files almost 40% smaller than JPEG images.
Google decided to develop the WebP because, according to its research, about 65% of the data that circulates on the internet correspond to images, of which, 90% are in the JPEG standard. Therefore, full adoption of a lighter format would decrease the amount of data being trafficked and reduce storage and processing costs, as well as making the loading of web pages faster.
Exif
Acronym for Exchangeable Image File Format, Exif is not an image format, but a kind of data table that contains information about JPEG and TIFF files.
Note that Exif provides various information about the image, such as the model of the camera that originated it, resolution, orientation (vertical or horizontal), creation date, exposure rate, shutter speed, among others. With Exif, it is even possible to include geographic location data in the image.
If you want to view a photo’s Exif, you can use image editing or viewing programs, since most of them have this function. Sometimes you don’t have to go that far: for Windows 7 or 8 users, for example, just right-click on the image, select Properties and, finally, choose Details. The Exif data will appear next.
