Click on the picture to see a brief summary of how Picasa can be used to create this effect.
Update (8/8/07): summarised here as well.
Step 1: take your source picture and use Picasa to make 2 copies (select File > Save a Copy, twice)
Step 2: select one copy and use the Effects > Soft Focus filter making the Size setting as small as possible and the Amount setting as large as possible. This can be repeated a second time if necessary.
Further adjustments can be made with the Tuning control panel in order to accentuate shadows or highlights.
The result will look something like this:
Step 3: select the other copy of the original and use Picasa to make a bright, high contrast copy.
In this example I converted the picture to black and white (Effects > Filtered B&W), selecting a colour filter that accentuated the contrast in the source image. (It is not required to convert the image to black and white – in this instance I was pleased with desaturating effect it brought to the final image.) I used Tuning to further manipulate the contrast, and Effects > Sharpen to enhance edges. The end result was this:
Step 4: The final step is to take the two processed copies and use Picasa’s Collage tool to blend them together.
Click on the Collage button and the Make Collage panel pops up.
Select Type > Multi-Exposure
and Location > Current Folder (or wherever you wish to save the final image).
A preview of the Collage appears and if you’re happy click on Create.
Warning: sometimes Picasa fails to produce the expected collage, using only one of the two selected images. The process in Step 4 may then need to be repeated in order to achieve success.