The main new features in 4.2 are Tool Tips for quick and easy explanations of all of the items in the tool bar, a Media Cache for improved Media loading times, and new paint on image processing modes such as: Gamma, Sharpen, UnsharpMask, BizarrePixelize, Randomize, and Channel Randomize. Blur, Convolve and RadialBlur have been rewritten for more speed, features and options. In particular Blur is now incredibly fast. Processing a 50x50 pixel blur on a 800x600 image now takes less than 2 seconds on an 060, with a huge 500x500 pixel blur taking just 3 seconds, and is fast enough to apply with the AirBrush!
Several minor changes include an enhanced Scale with improved quality and feedback, an improved Text tool, a reduction in the memory need by Photogenics by one megabyte (now uses just two megs with no images loaded), various overall speed improvements, keyboard shortcuts for zoom and pan (>< to Zoom In/Out, arrow keys scroll), plus tweaks to the user interface.