Images processing and editing for a web use
This month's content :
By "digital image processing", we understand a set of techniques enabling the user to modify such an image in order to enhance it or to extract datas from it, so that it can be used in web pages.
For example, to correct small altering aspects, to lighten or to darken the image, to work on the colors, etc. are all techniques that enhance the digital image rendering on your screen.
The images used on the web are recorded in 3 main formats :
- JPEG : my_image.jpg
- specifically designed for digital pictures (e.g. photography)
- supports millions of colors
- PNG : my_image.png
- designed for complex graphical rendering
- supports up to several millions of colors and is ideal for transparencies and gradation effects.
- GIF : my_image.gif
- the most widely-used format
- supports animation effects
Why should I edit
an image ?
-
To enhance the image's quality
This means to obtain for your image a better visual rendering and the adequate sharpness so that it is suitable for a web use.
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To improve the web pages loading time
The heavier and larger is the image, the longer it will be to be uploaded and displayed on your web site. As a matter of fact, the pages load time is a key decision criterion for the visitors of your web site.
How to edit
an image ?
The digital image processing, also commonly known as "images retouching", is applied to the digital images (or pictures) in 4 main phases :
- Lower the image resolution
The image reslolution defines the number of pixels on the entire image. The higher is this number, the better is your image's quality. It is measured in dot per inch or pixel per inch (dpi or ppi), which corresponds to 2,54 cm.
The standard resolution for a web image is of 72 dpi.
The smaller the image will be, the faster it will be uploaded on a web page.
It might looks strange, at first sight, to try to "lower" the image's quality, but in fact we aim at reducing the image's
weight, that is, compressing it. Usually, the quality is measured in byte (bytes - megabyte, mb, etc.) or in percentage. 60% is a good ratio to keep an image with an acceptable sharpness.
- Delete non-essentials information (optional)
These information relate to the digital camera parameters (date, time, etc.) and these are not used by the browsers. It is then perfectly possible to delete them. A freeware application can do this : PureJPEG (N.B. it works in command-line mode only)
Images
banks (resources)
An image bank (or stock photography) is a data bank that has aggregated several thousands to hundreds of thousands of photographs, images and illustrations. The pictures from these images banks are often used as illustrations in magazines, newspapers, brochures, web sites, packaging and with medias, advertisement and as ornamental supports, either in electronical or printed forms.
Among the many image banks available, the Keonnected Team has selected for you some of the best-known free-of-charge or paying ones:
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PAYED SERVICE
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FREE-OF-CHARGE
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Fotosearch
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Fotofree.com
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Getty Images
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Dexhaus
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Fotolia
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Digital Dreamers
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Iconos
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Turbo Photo
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Wikimedia Commons
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Animation Factory
|
Types
of licence
The images available can be used, provided that you have checked, for each image, the type of licence granted to the users !
Each image has a precise type of licence that defines the strict limitations of its use :
The "right-managed licence"
is the classical licence model used for many years by the usual images banks. The price and the restrictions to the use of the image are set case by case according to the client's needs (e.g. for a magazine cover, sold nationwide, at 125 000 copies.)
The royalty-free licence
appeared at the beginning of the years 2000 with the Internet development and the increased needs to use images. This licence broaden the framework of use of an image compared to the right-managed licence model. A "royalty-free licence" grants,
once acquired, an unlimited use (in time and space) on all types of supports.
However, keep always in mind that «royalty-free» is
not
meaning «free of all rights or royalties» ! For one thing, this type of licence is a payed-for licence, and secondly, it defines a strict framework for the use of the acquired image. For instance, it is very often forbidden to use one image ways or in contexts that could harm, misrepresent or damage the model(s) shown on the image.
The tools
to process and edit images
Similarly to the images banks, they are numerous tools to process and edit images that can be found on the Internet. They are targeting a very large audience and varies greatly in functionalities, from very simple software to use to much more professional and complex applications.
All of them allow you to process images following the above described phases, so that the final result will be of an higher quality image, ideal for your web use.
Among the ones that have been selected by the Keonnected Team, you will find the
Adobe® software suite (Photoshop®, Illustrator®, ImageReady®, etc.) which are tools aimed for a professional use (paying licences) or
GIMP (a very powerful editor, completely free-of-charge & open-source) and
Image Resizer (no-charge).
In addition, we recommend the use of a freeware, easy-to-use, yet powerful editor, and quickly-installed software :
Give it a try and test for yourself the ease of use and the numerous functionalities that the Paint.Net® editor is offering !
