Transfer modes are working in the paint widget! "Blend" and "Blur" painting work, with variable levels of transparency.Haven't done "colorize" or "rub-through" yet, but those should be pretty simple.

Other things that got done include:
• Optimized redrawing of images for various widgets when "imageChanged" signal is recieved
• Finished scratchpad preview area
• First cut at serialization of image sets

Here's a screenshot.