Process-control, quality assurance, real estate, insurance, surveying, construction ... the list of industries and business types that have come to depend on photographic and video documentation is large and growing, especially as inexpensive digital cameras and camera phones proliferate.

Even in businesses where photos and videos, per se, aren't central, they may still find widespread use in specific activities such as asset management, human-resources documentation, trade-show activities, Web-site illustration, instructional materials, brochures and catalogs, and so on.

A number of free and by-subscription services have cropped up to help make better use of some of the billions of digital images being captured each year: These specialty file-sharing services let their users place photos and videos -- and in some cases, any file type whatsoever -- in private or public areas for sharing, group collaboration, archiving, for illustrating auction sites, for use on message boards, in classifieds, on live journals and blogs, in online photo albums, and almost any other use you can think of.

Although you can use an ordinary Web site for sharing photos or videos, many of these specialty image-sharing services offer easy-to-use custom tools that are optimized for processing and organizing visual materials. There's no domain name to register or maintain, no hosting service or server to worry about. And, because these services are free or extremely low-cost, users can create accounts as needed and on their own, with no Webmaster assistance required. Uploads usually require only a Web browser and a password to the site -- no Web-site-creation tools are needed, and no special knowledge or training (e.g., HTML) is required. The sites usually even present the uploader with a finished URL for easy sharing of the uploaded materials, with no behind-the-scenes Web site knowledge needed.

Free? How Do They Survive?
Some of these services are totally free, and we'll get to those in a moment. Others, such as PBase, offer free trials, then charge a minimal amount for ongoing service. Pbase is one of the best image-sharing services, but even so manages to get by on relative pocket change: Pbase charges a paltry $23 yearly for 300 megabytes of photo storage, with additional storage space available in 300-Mbyte increments, with a modest quantity discount available.

In terms of photos, 300-Mbytes will hold something like 1,200 jpgs at an average of 250 Kbytes. (Higher-resolution photos would consume more space, of course; lower resolution photos would consume less.) The space is recyclable; once photos are deleted, the space they occupied is returned to the available pool. Pbase places no limits on the number of downloads, and assesses no extra charges for bandwidth consumed. As such, it could be a great way to host photos for a Web site that otherwise resides on a bandwidth-metered server: The basic pages could come from the Web host, but the bandwidth-intensive images could come from Pbase.

Unlike fee-based services, the free services do it a little differently: Most of those are supported by advertising, which raises two issues. First, most of these free sites prohibit "hotlinking:" that is, you can't link directly to your photo or video, in isolation. Instead, your visitors will see your image or video on a complete page, as set up by the free service; the page will include their ads around or alongside your image or video. That means these services may be OK for basic photo and video sharing, but won't work if you want to embed your images or videos on another page, such as on your Web site or on (say) an auction site: All you can do is link to the image-hosting service's own pages, which will display your photos and videos, along with their ads.

And that leads to the second issue: While many of the image-sharing services are safe for work environments and are "family friendly," others support themselves with ads mostly or entirely of an overtly sexual or "adult" nature. So, you need to be careful in choosing free sites to make sure the content that will surround your photos and videos meets with your, or your company's, standards. (In contrast, a paid site, like Pbase, contains no advertising of any kind, and seems to police its users more rigorously, and so appears to avoid this problem.)

But perhaps the best way to sort out these differences is to look at some real-life example sites