taking Photos for web pages

How to optimise photos for web display and short download time
building a scenic collage for web page display - keeping in mind download time and large file sizes. Taking good digital photos with correct light requirements - Creating a local (Offline) gallery of stock photos - walking, walking with dogs, biking with local backdrops, recreational/sporting facilites, schools etc. Ideal and consistant photo sizes, presentation of images like watermarks, cropping (there could be lots to cover or just a quick overview - there may be too many software programs out there to cover all this in one session).
Creating an animation where an image fades into the next image.
Images just make a page more interesting to view.