A quick screenshot of loading times with PNG images between the new version 3.1 and the old version 0.8.2 (which was what I had handy for testing, but still the same internals as 3.0)..
For 100 loads of a massive 3000x2229 PNG image:
v3.1 took 19.2 seconds.
v0.8 took 28.7 seconds.
That's an improvement of what? Cut off about 1/3rd of the time to load the file 100 times, so that seems like a rather nice improvement on my machine!
For BMP files, this is the times I see for a 2560x1920 image:
V3.1 took 6.4 seconds.
V0.8 took 14.8 seconds.
Less than half the time to load BMP images with the new version under the hood.