Flickr

Flickr lets you upload photos in multiple sizes, manipulate photos online, post photos to most common blog tools, set the privacy level of each photo individually, and accepts photos uploaded from cameraphones. You can tag your photos and add notes to them, and allow others to do the same.

Fotki

Unlimited photo storage, plus a wide range of tools for sorting and categorizing your pictures. You can choose to share them or keep them private. You can also apply various manipulations to them via your browser.

ImageShack

Free image hosting solution which can be used to share pictures with friends, as well as to post images on message boards and blogs. Images are limited to 1.5MB in size. You can directly link images on websites and online auctions.

ImageStation

Unlimited photo storage in compressed format (once uploaded, you no longer have access to the original high-resolution files), plus up to 15 minutes' worth of free video storage. Photos are stored for 12 months from the date they are uploaded. Several premium membership tiers are available, introducing various additional features.

iWebPhoto

Limited free photo storage with space for 15 pictures of up to 1MB each. Premium service tiers offer additional features and storage.

MyPhotoAlbum

Free online photo and video storage service. Individual photo uploads limited to 8Mb (and 100Mb per video). Unlimited space, so long as at least one premium product is purchased every 6 months. You can personalise your photo album in many ways, and invite others to view your photos and videos.

Photobucket

Free video and photo sharing service with 1GB of disk space and 10GB of monthly bandwidth. The maximum size of a single image is 1MB, and 3 minutes for a video clip. You can create albums and slideshows, or link your photos directly into websites, email and IM. The premium service offers more storage space and bandwidth, plus additional features.

Uboot

Free photo and video hosting, plus the ability to add tags, comments and descriptions. Free service also includes blogging tools and a personal profile page.

WebShots

Free online storage for up to 240 photos, plus the ability to download 5 professional-grade photos per day. Premium service level with additional features and significantly more generous service limits.

Zeec

Free online photo and movie storage with the ability to upload pictures from mobile photos, by email or via the web. You can arrange the material you've uploaded into albums, and decide whether to make them public or private.

Worth a look if you're willing to pay...