Hot on the heels of the latest Photoshop Elements 8 (click for full review) comes the new Picasa 3.5.

This adds a few  features across the board, such as a revamp of importing and various interface tweaks, but the clear focus of the new release is on in-depth tagging of images via a new side panel that offers three tabs for applying text-based tags, locational geodata and new face-based tags.

To be honest my heart sank when I heard this – what I’ve always liked about Picasa is that it keeps things simple and doesn’t treat managing your photos as a full-time job. Moreover I’d recently come away less than impressed with Photoshop Elements 8’s new face tagging not so much because the technology doesn’t work (it does though imperfectly), but rather because the gains aren’t worth the effort.

So how does the new Picasa 3.5 shape up?

Brilliantly.

I’m still too lazy to be a huge fan of intensive text-based meta tagging but Picasa clearly needed to improve its feeble floating Keywords panel and the Tags panel certainly does that. Likewise I don’t suppose many users ever bothered to geotag their their images via Google Earth, but now you can simply call up a Google Map in the Places panel and drag-and-drop your images onto it. Excellent.

The real revelation though is face tagging. Select a folder or album and Picasa does a great job of pulling out the faces in your images – or at least all those looking at the camera – and listing them in the People tab with an “add a name” label next to them. I half-heartedly marked up a few photos of family members while idly thinking how nice it would be to have a week off to go through my entire collection of thousands of images like this…

But then I noticed that Picasa 3.5 had added a new People category to the main navigation panel down the left of the screen. I clicked on the “me” tag and discovered that, based on just one image that I had tagged (with comedy glasses), Picasa had found another 17 images that it was confident was me and another 160 or so that it thought was me. Incredibly all of them were, including many in bad hats and blonde wig (don’t ask). Confirm these suggestions and Picasa goes and finds some more, and then more again and all with astonishing accuracy. I generally don’t like having my photo taken (and it’s my camera) so the fact that  Picasa has found over 300 shots of me without a single mistake is remarkable – and more than enough.

It was a similar story with other clearly-defined adult faces, but accuracy with my five-year old twins (non-identical) was unsurprisingly far more hit-and-miss though I think this might well have been because I didn’t bother finding clear images to tag originally (and because I can never get Robbie to look at the camera).

In any case it really didn’t matter because it’s incredibly simple to select the incorrect suggestions and drag them to the right tag. In fact the whole process is actively enjoyable.

That’s something I never thought I’d be able to say about the prospect of tagging thousands of images containing even more faces.

Ultimately human nature means that most people are most interested in pictures of people, and especially pictures of themselves and their friends and family. With another brilliant search technology under its belt – bitmap-based faces – Google makes a previously unthinkable chore into a real joy. Superb.

And did I mention that it’s free?