Picasa will start by enlarging the image into a desired size (which can be upto 1000% times larger than the original dimensions). It will then split the magnified copy of the image into multiple smaller images of standard paper sizes like A4 or A5.
That's it - you then print these smaller images at home or at your nearest photo shop, and glue or tape them together on any wall to create a poster or mural.
The following example shows different images generated by Picasa using a screen capture of the Blogger homepage (each image is of size 8.5"x11" and can be arranged as a wall poster)
Step 1: Open the image in Picasa that you'ld like to convert into a poster or banner.
Step 2: Select Create from the menu and choose Make a poster. Select the magnification level and the default paper size (4"x6" or 8.5"x11").
Picasa will instantly create multiple images in the same folder that you can print and paste on any wall or carboard sheet.
Not just photographs, you can also apply the same technique to print sales figures, Excel Spreadsheet graphs, Powerpoint presentation slides or even classroom posters in large format without requiring any extra budget or resources.