This build loads the next and previous image ahead of time in the background during image playback. This makes image switching almost instant assuming you spent a little time looking at the current image. (if you hammer through images as fast as possible, this method won't be any faster since the old build could already use 100% of the muscle the CPU had)
The cost is that it takes more memory during image playback. A decoded 10 MP image takes over 40 MB of memory. (which is about double what MC itself takes when playing music and browsing the library!)
Anyway, play with image playback this build and let us know what you think. Thanks for any feedback.
(NOTE: As an aside, this change combined with holding "Shift" while switching images (to preserve zoom and scroll) makes MC a great pixel-peeping tool if you're trying to pick the sharpest image from a burst, etc.)