Slow image display

Visiting this page with NetSurf build #1257 on my Omega (300MHz
StrongARM, RISC OS 4.39, 1920x1080x16m) is very slow:

http://stardot.org.uk/forums/viewtopic.php?f=16&t=6753

It takes 66s to display, of which 45s is spent on the big image. And
this being RISC OS, that's 45s of non-multitasking :-(

NetSurf uses about 80MB of memory to display the image, then after the
page has been open for a minute, it releases most of that memory.
Great, except then if any of the window needs redrawing there is
another 45s wait :-(

Saving out the image, the OS can display it in only 1s, so why does
NetSurf take 40 times as long?

I tried switching the Image options to "Use OS" and the image memory
up to 100MB but it made no difference.

Bryan.

--
RISC OS User Group Of London - http://www.rougol.jellybaby.net/
RISC OS London Show - http://www.riscoslondonshow.co.uk/