If you'd just like to use pre-existing images for your website, you'll need to make sure you don't fall foul of any copyrights.
CanStockPhoto.com offers over 15 million professional royalty-free
photos, illustrations and footage at affordable prices. They offer free weekly downloads with tens of thousands of new images added every week, making it a great site for people who need quality photos for a variety of purposes.
PageTutor offer links to plenty of image resources.
FeebleMinds offer free clipart and other royalty-free images.
AnimatedGifs are available for free by the bucket load here - about 5,000 of them!
FreeStockPhotos has a nice selection of photographs;
RegardIt offers free landscape photographs as does Jan Csernoch's
PhotoTravelogue and the
MorgueFile site is another rich source of excellent material.
Do make sure you take the time to read and understand which images you are permitted to use for free, and under what circumstances, before going ahead.
To create your own images you will need an image editing program. Some of the commercial products for professionals are brilliant, but cheap they are not! Fortunately, there are some great free alternatives out there...
PhotoshopGuides has vast range of tutorials to help you make the most of the ultimate professional graphics program,
Adobe PhotoShop and you may find some of these very helpful if you are fortunate enough to be able to afford to have this excellent software. If not, don't worry...
Gimp is a free image editing program that works very well. For all the help in the world with using it, read Grokking The Gimp online, download it as a tarball or buy the printed version...
There are more free image editing programs on Honor Mission's Fun With Freeware 1 Fun With Images page site, elsewhere on this domain...
DynamicDrive offer lots of useful things, amongst them a free online image optimization service...