Illustrating your articles with beautiful and relevant presentation images is essential to attract the public eye. With today's technologies, nothing could be simpler than taking a digital photo yourself, which you can then place wisely within the text to be illustrated.
But sometimes, for geographic or time constraints, it is necessary to turn to the services of a website offering quality images.
It is very easy to find images on the web, but it is already more difficult to find good quality images at reasonable costs. Because you surely don't want to end up with poor quality images in your important Powerpoint presentation. Here you will find some relevant sites that will make it easy for you to find the right illustration images for you:
Getty Images : Can be expensive (between 50 and 500 €) but has professional quality photographs.
Google Images : Images are free but you must have permission from the authors to use images.
Flickr : Good selection of amateur images, but permission must be obtained from copyright owners.
Wikimedia : Substantial amount of photos but you have to be careful with restrictions on usage rights.
Fotolia : Inexpensive and quality images.
There are plenty of other places on the web that offer illustration images, but always pay attention to usage restrictions so you don't get bored.