One of the big advantages of Flickr is that photos can be uploaded without the need for complicated re-sizing. If you have a Pro account then even large files from digital SLR cameras can be shared at full resolution, and a free drag-and-drop desktop uploader utility is available, which makes it even easier to add photos to your online collection. Basic Flickr accounts are free, but are restricted to uploading 100MB of images every month, and very large images are automatically resized for sharing (although the full-size image is still stored in case you upgrade later). Pro accounts cost $24.95 for a year, but have no upload restrictions, and allow full-size images to be displayed and shared. If you make your online galleries public then anyone can view and download them, which has led to a few controversial cases where user's photos have ended up being used commercially without their permission, but photos displayed on Flickr are covered by the Creative Commons license, and users can set various licence conditions, which provides some measure of legal protection against this type of abuse.
A major rival to Flickr is Google's Picasa Web Albums. Also launched in 2004, Picasa differs from Flickr in that the main component is a photo organising and editing program which can be downloaded for free and installed on your computer. It has an easy-to-use interface, and automatically searches your hard disk for any and all image files, making it easy to view and sort even large collections of pictures. The editing functions are limited to basic tweaks and fixes, but are ideal for preparing photos for sharing.
Picasa Web Albums offers one gigabyte of free storage space, with more (up to 400GB) available in a progressive series of paid upgrades. Photos can be uploaded either individually or by album, at full size or automatically resized for faster uploading and viewing. Like Flickr, albums can be set to be private or open to public viewing, and can also be linked to a map location. Picasa is growing in popularity, and offers probably the best level of service in its basic free-of-charge form.
Users of Macintosh computers will be familiar with the iPhoto software, installed as standard as part of the iLife package supplied with all new Mac computers. It shares many features with Picasa, including basic image editing, the ability to organise photos into albums and slide shows, and also the option to upload images to the .Mac Web Gallery, where they can be shared with your friends and family.