Displaying a new photo: too much blinking and loading

Another little UI annoyance.

First a little glitch that could be easy to fix:
When I switch to a new photo photolab reverts to displaying the background color for a short time. That produce a kind of flashing.
I feel it would be better to leave the previously displayed photo until the next one is loaded and ready to be displayed.
For some reason it sometimes behaves like this, maybe there’s some caching already but it randomly picks one out of ten photo to cache it?

Second idea that would involve more work:
While you’re at caching to enhance the user experience, would it be possible to precalculate the photos in the background?
My computer is idle most of the time so I am annoyed that it only starts working when I want to see the picture. It could have done that way before and immediately show the result.

On my Mac, DPL does something when a folder of images is opened: CPU load increases for quite a while during which the DPL gui gets slow and annoying. DPL does not scale well and I feel that DPL could do much better than to calculate the whole lot, specially when you open a folder just to see what’s in it…