The biggest name in photo software for many years has been Adobe's Photoshop. But, as more and more photos migrated online, Adobe became concerned that people would associate photo software less with its own locally installed programmes than with web-based products and services.

So, last month, the photo giant introduced Photoshop Express, its free web-based service for storing, sharing and editing photos, in an effort to compete with established online photo services such as Yahoo's Flickr, Google's Picasa Web Albums, or the photo-laden Facebook social-networking service.

Photoshop Express has many of the same features as Flickr and its ilk. It gives you two free gigabytes of photo storage. But Adobe is hoping to make its mark with editing.

Most online photo services offer little or no editing, assuming you will do that using software on your computer before you upload your pictures. But Photoshop Express, borrowing from Adobe's deep knowledge of photo editing, offers the nicest set of web-based editing tools I have seen. They are sophisticated for a consumer application, yet easy to use. They edge out those in Picnik, a pioneering web-based photo editor I hailed last year.

These slick editing tools are not only available for use with photos you have uploaded from your hard disk. You can also use them to edit pictures stored in your accounts at Facebook, Picasa Web Albums and another big photo-storage service, Photobucket - all without leaving Photoshop Express. You can even move pictures between Photoshop Express and these three services just by dragging and dropping.

Adobe's new service is available in the US only, at www.photoshop.com/express.

I have been testing Photoshop Express and its service overall is pretty good, even though it is still labeled "beta".

It is a nice example of the Web 2.0 trend, where programs accessed via a browser can look and feel like applications that live on your computer.

But Photoshop Express is rough around the edges. It can be slow at times, and it is missing some obvious features, like the ability to easily download publicly shared pictures from other members or to print photos. Adobe says it is working on these things.

Photoshop Express is not meant to replicate all the features and power of Photoshop. It's more like a Web-based version of Photoshop Elements, Adobe's consumer software package.

I tested Photoshop Express on multiple computers: PCs running Windows XP and Windows Vista, and Macs running Apple's Leopard operating system.

I used it in all three major web browsers: Internet Explorer for Windows, Firefox on both Windows and Mac, and Safari, also on both platforms.

It worked fine in all of these operating systems and browsers, though it does require Adobe's free Flash software.

For my tests, I uploaded from my computers dozens of photos, from very large images captured with good digital cameras to smaller shots from cellphones.

All were handled perfectly by Photoshop Express. I also opened and edited pictures in Photoshop Express from my accounts on Picasa Web Albums and Facebook. All of this worked well, though uploads of large images can be slow if your Web connection is pokey.

Photoshop Express is a handsome product, presenting your photos on a gray background with controls and features arrayed at the top and bottom, and down the sides, in a logical, clear manner. Your own photos are presented in a section called "My Photos", and can be organised into albums.

Photos that other Photoshop Express users have chosen to publicly share are organised into collections called "Galleries", which can include multiple albums.

You access these community photos by simply clicking on "Browse" or performing a search.

For each album you create, you can choose to share it publicly or to keep it private. Whichever option you choose, you can email friends either a link for viewing the album or a single photo.

Your own photos can be downloaded at a variety of resolutions, including original size.

When you view shared galleries or albums, they appear as slide shows. You can select a number of slick effects by which the slides appear, allowing them to zoom and glide into place from various directions.

The editing features really stand out. In addition to standard tools such as auto-correction and red-eye elimination, Photoshop Express lets you touch up areas; adjust exposure, saturation, and lighting; and even make certain colours pop - so grass is greener, for instance.

And, in most cases, it shows you small example images illustrating the changes, then previews those changes in the larger main image just by moving your mouse over the example. You can revert to your original at any time.

Unfortunately, there are a number of problems. Photos, especially large ones, can take awhile to appear in the editing module and to snap into focus.

Captions sometimes get lost or mixed up when you move photos to other services. You can view shared albums only as slide shows, not as individual photos.

Still, Adobe has made a good start with Photoshop Express, and it is worth a try if you want better online editing for your pictures.