Chapter in this post:
The file extension ".jpg" or ".jpeg" is usually found in image files. The image format is supported as an output format by DSLR or compact digital cameras, for example. Due to the compression and the associated loss of image information, however, photographers prefer to choose the [RAW format-> raw]. This saves the image data without loss and also in a form that allows the photo to be "developed". This means that you have significantly more color information than with the JPG format and can therefore "save" even underexposed photos. The disadvantage, however, is that the RAW files require considerably more storage space than JPG files.
Most of the graphics on websites can also be found in the formats [GIF-> gif] or JPG. While the GIF format is more suitable for graphics with little different and two-dimensional colors, the JPG format is best suited for photos. Line graphics or cliparts are also less easy to save with the JPG format. The edges of the strokes offer high contrast, which in turn leads to fractals when compressed. You can see this clearly in the three sample images with the text.
The advantage of the JPEG format is that it allows the compression rate to be set flexibly between 0 and 100, with the value 100 corresponding to the lowest compression and the highest image quality. If you go further down, the loss of image information in the photo becomes more and more visible. You can see fractals, puke formation and image noise, which is particularly noticeable in flat, dark areas. In Wikipedia I could read that there was even a lossless compression gives. I assume, however, that this corresponds roughly to the PNG format in terms of storage space savings.
While animations can also be created from image sequences in GIF format and areas can be provided with transparency, in JPEG format neither an image sequence nor transparency information and certainly no level information is provided. So it is actually a bit "limited", but due to the high compatibility on the Internet and with technical devices, it is still the most widespread image format on the Internet.
For media designers who create print documents, it is certainly interesting that JPG is also the CMYK format controlled. However, it is hardly represented in the print sector. File formats such as [.ai-> ai], [.tif-> tif], [.eps-> eps] or [.pdf-> pdf] predominate there, as these files store much more image information.
There are already some programs on every modern Mac that can handle .jpg files. These include:
The following programs are more suitable for professionals:
In the following photos you can see how an image changes when you select 100, 50 and 0 as the value for the image quality for JPG export. The change in image size is also interesting: 324 kB, 61 kB and 20 kB.
Image quality test with text in JPG format
In the following images I used two fonts to show how the increasing compression rate affects the appearance of the font margins. You can clearly see that the JPG format is not the best choice for saving graphics with typography.
You can quickly see that the file size is not really interesting for the typography either. I exported a GIF with the fonts as a test, which works without loss and represents the text 1: 1. This only had a storage volume of 21 kB. You can see immediately which is the better choice here.
For those who have to do with editing and exporting images on a daily basis in their job, I recommend the "[Image Editing Primer-> Image Editing Primer]" - Volumes 1 and 2. This is an instructive and amusingly written book on the subject.
Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.