Cool idea, I thought.
An hour or two later, I had my new collage banner: a row of hats framed with a sky blue border.
The old banner (also made with Picasa) showed an extreme close-up of a hat crocheted in wildly colorful Italian yarn.
I left the shop name off the new banner. Right under the banner it says "Hats by Elvee/Stylish handmade hats and crochet patterns," so I decided that my new banner didn't need to repeat the shop name.
I applied the special effects setting for "HDR-ish" -- high-dynamic-range imaging -- to make the little parade of hats really pop.