If you are going to redistribute this image online, a hyperlink to this particular page is mandatory.
HTML:
<a href="http://www.publicdomainpictures.net/view-image.php?image=6888&picture=red-gerbera">Red Gerbera</a> by Teodoro S Gruhl
Note:
If you intend to use an image you find here for commercial use, please be aware that some photos do require a model or property release. Pictures featuring products should be used with care.