The three megapixel Optio 330 was first announced back on 29th May 2001, later, in September Pentax announced the Optio 430, a four megapixel upgrade to the 330. The two cameras are essentially identical apart from the additional image size of the 430. Body design, control layout and menus are all exactly the same.
Because of this, and because I've already reviewed the Optio 330 much of this review is based on the Optio 330 review. If you've previously read that review you may wish to skip to the photo tests and image quality comparison.
The Optio 430 measures just 92 x 62 x 31 mm (3.6 x 2.4 x 1.2 in) and that makes it only just bigger than Kyocera's tiny S4. Fully loaded (including battery & CF card) the 430 weighs in at a pocketable 240 g (8.5 oz). The Optio 430 has a steel case, four megapixel sensor, three times opstical zoom, proprietary Lithium-Ion rechargable battery and Compact Flash Type I slot.