Image Formats JPEG, GIF, PNG and Other 1
Technology

Image Formats: JPEG, GIF, PNG and Others

Introduction

In the early days, computers were able to display only lines text. With the constant improvement of resources graphics, both hardware and software, shapes, and colors varied became part of the routine of those who use these machines, a situation that, gradually, resulted in the the emergence of various formats of images. A lot of these became popular with the Internet. It is the case of the standards, JPEG, GIF and PNG, whose main characteristics the AbbreviationFinder displays the following.

Break, the text will also show briefly other formats known, but less used: Bitmap, TIFF, RAW, SVG and WebP. Finally, explain what is Exif. Let’s check out?

JPEG format (JPG)

The format JPEG, whose acronym stands for Joint Photographic Experts Group, had its first specification released in 1983 for a group that bears the same name. It is one of the standards most popular of the Internet by combining two characteristics important: offers reasonable levels of quality image, and generates files of small size when compared to other formats, facilitating its storage and its distribution.

JPEG allows this because it is a format that uses compression of images. But, what is it? In a few words, compression consists in the elimination of redundant data in the files. In the case of images, it is possible to make the compression so that the withdrawal of information does not harm the quality (lossless- without loss), as well as it is possible to use levels the greatest compression that causes losses visible (lossy- with the loss).

This last is what happens in JPEG: in this format, the higher the compression level, the smaller will be the size of the file, but the worse the quality of the image. The compression level can be determined in programs of treatment of images. Each time a the same JPEG image is saved, is usually to lose quality, since, usually, the software that is used to treat it apply compression, the same minimum, every time that this action is carried out.

The JPEG is able to work with almost 16.8 million colors (24-bit). This feature, combined with the ability compression that reduces the size of the files makes the format an excellent option for the distribution of photographic images, so much so that the format is very used for the generation of photo cameras digital. This is because, even if there is a loss of quality, this occurs way little or nothing perceptive, since that, of course, not there is “abuse” of the use of compression or bailouts frequent. In the case of activities professionals, it is recommended to use formats that preserve the quality.

GIF format

Acronym for Graphics Interchange Format, the GIF is another format quite popular on the Internet. It was created by CompuServe in 1987, as well as JPEG, and generates files of reduced size, however, your use is not very common in photographs, since that is able to work with only 256 colors (8-bit). For this reason, your use is very frequent with icons, illustrations or any image type that does not you need many colors.

There is, however, a feature that makes the GIF format be known until today: thanks to a review carried out in 1989, the standard now has the ability to support animations. In other words, the GIF went on to allow the insertion of a sequence of images in a single file. Thus, when a GIF of this condition is displayed, each of the inserted pictures is shown following an order, giving the user the sense of movement.

The GIF format still has another differential: it is able to allow an effect known as transparent background. This means that a file GIF may have areas of the image that assimilate the color of the location where it is being displayed, as it were, in fact, a transparency. For example: if a GIF image is being shown in a Web page with a green background, the areas “transparent” of the file will be displayed in the same color.

The GIF also uses compression, but this does not cause a loss of quality, even if the image is saved several times. Here, there is a curiosity: the algorithm compression the most common of the GIF is the Lempel-Ziv-Welch(LZW), whose patent belonged to Unisys. Apparently, CompuServe I didn’t know that. As a result, in 1995, Unisys started to charge companies who are responsible for programs image editing by the use of the algorithm in question. The patent expired in 2003, making the charge no more be permitted.

PNG format

The format PNG, short for Portable Network Graphics, it is one of the latest standards, with its first specification as it emerged in 1996. Its development was motivated, in part, by restriction of patent existing in the GIF format, as explained in the previous topic.

The PNG meets, therefore, the features that have made the GIF so well accepted: animation, transparent background and compression without loss of quality, even with bailouts contained in the file. However, with a large differential: supports millions of colors, not just 256, and, with this, a great option for photos.

In the aspect of animation, the PNG, by itself, not have such capacity. What happens is that there is a variation called APNG (Animated Portable Network Graphics), which enables this feature. The schema is the same as the default GIF: a sequence of images placed in a single file. In this case, the first image it is a PNG file that is “normal”, which is displayed in situations where, for some reason, the animation can’t be performed. There are also a variation called MNG (Multiple-image Network Graphics) that has the same purpose.

Images in PNG format have the extension .png, even in the variations of animation, although, in the latter case, it can be used also in the names .mng and .apng.

PNG is a free format, created from the beginning to be used in any application without the need of payments of allowances or the like. Your use it is endorsed by the W3C.

Note that the image in JPEG format has a quality that is acceptable for a simple note, but if you notice well, you will notice that the figure in PNG shows detail with more clarity. This is because the first went through a process of compression that reduced their size, but have committed a little of their quality. The the second figure, in PNG, also went through compression, but does not lost quality.

As the original image is rich in color, lost a lot of quality when it was converted to GIF, making it clear that the format not suitable for photos like this.

Other formats of images

The formats of JPEG, PNG and GIF are the most widely used, especially on the Internet, but obviously, they are not the unique. The following gives a brief description of some well-known patterns, but less used.

Bitmap Format

The Bitmap is one of the formats of images more old, and also one of the most simple. Widely used in the systems operating Microsoft Windows, the images in this format can support millions of colors and preserve the details.

However, the files in this pattern tend to be many great, since they do not use compression. This process it is even possible in images with 256 colors or less, but is not common.

Files in the Bitmap can have an extension .dib (Device Independent Bitmap) or BMP (this is the last standard) and Microsoft Windows do not support the “transparent background”.

TIFF format

Acronym for Tagged Image File Format, TIFF is in a format widely used in professional applications,as images for medical purposes or industrial. Created in 1986 by Aldus, company later acquired by Adobe, is also widely applied in the activities of scanning, such as scanner and fax, which, in fact, motivated its development.

The TIFF format provides a large amount of colors and excellent quality image, which considerably increases the size of your files, although it is possible to soften this appearance with compression without loss of information.

An interesting detail is that the TIFF format supports the use of layers, that is, one can use versions differentiated of the image to be imaged in a single file.

Images in TIFF usually use the extension .tif or .tiff and support the “transparent background”.

RAW format

The format RAW (translated, something like “cru”) is a little different from the others. This is a pattern that keeps all the data of a photo, such as this was generated in the digital camera, without application of effects or settings. Because of this, offers high quality image and greater color depth. Of course that when a RAW photo is compressed, there may be loss of quality, even if slight. In spite of this, this option it is often considered, as the images on this standard often result in really large files.

A good portion of the cameras allows the user to choose the format of the photographs, being the RAW an option. And why choose it? As the files in this pattern are “pure”, the editor has the freedom to use the image of the the way it was captured and apply your own effects or adjustments. The end result can be a photo beautiful, even when this is subsequently converted to a format more“wearable”, such as JPEG or PNG. This causes the RAW is nicknamed “the negative of digital cameras”, although not if it is necessarily that.

Files in the RAW format admit various extensions. This because each manufacturer of digital camera works with your own specifications.

SVG format

SVG stands for Scalable Vector Graphics and, as the name indicates, consists of a pattern that works with vector images. It is also a open format, developed by the W3C and that came about officially in 2001. Instead of being based on pixels, that is, the “dots” that make up the images, such as in the patterns shown previously, the SVG uses the XML language to describe how the file should be.

Thanks to this, the SVG can work well with both figures static and animated images. In addition, bybe a standard vector format images can be enlarged or reduced without causing loss of quality.

And the WebP format?

You may hear much talk of WebP. Or not. This is an image format introduced by Google in October 2010 which proposes to allow the generation of files with reduced size and, at the same, good image quality.

For this, the standard uses a compression scheme that causes the loss of quality is the lowest possible in the eyes human. According to Google, this method is able to generate files almost 40% smaller than JPEG images.

Google decided to develop the WebP because, according to their research, about 65% of the data circulating on the Internet match the images, being that, of these, 90% are in the JPEG standard.Therefore, the adoption of a format that is more lightweight would decrease the amount of data traffic and reduce costs storage and processing, as well as leave loading Web pages faster.

Exif

Acronym for Exchangeable Image File Format, the Exif is not a the format of the image, but rather a kind of data table that contains information about JPEG and TIFF files.

Note that the Exif information about the image, such as camera model that originated it, resolution, orientation (vertical or horizontal), creation date, rate of exposure, shutter speed, etc. With the Exif, it is even possible to include data from geographic location in the image.

If you want to view the Exif of a photo, you can use editing programs or viewing images, since a good part of them has this function. Sometimes there is no need to go so far: for users of Windows 7 or 8, for example, just click with the right mouse button on the image, select Properties and, finally, choose Details. Exif data will appear then.

Ending

In the face of so many options, which image format to choose? As you saw in the course of the text, each pattern has a the proposal, a purpose, therefore, the most important of all is knowing what each format can offer to you you can make the choice most appropriate to your needs.

Image Formats JPEG, GIF, PNG and Other 1