how to load huge images with imageJ (on windows64)
First, you need to install the “Java Runtime Environment (JRE) 5.0 Update XXX” from sun, make sure you get the “Windows x64”-Version from the page (It doesn't matter if you download the AMD64-version, it will work on intel)
After you've done this, open ImageJ.cfg (in ImageJ-folder) with your favourite text editor and change it to:
C:\PROGRA~2\ImageJ\ C:\Program Files\Java\jre1.5.0_17\bin\javaw.exe -Xmx5000m -cp C:\PROGRA~2\ImageJ\ij.jar ij.ImageJ
Make shure that you add the correct paths (pay attention to “Program Files (x86)” in 8.3-Notation and stuff like that. This makes ImageJ use the 64bit-Version of Java (the 32bit-Version can still be left installed…). -Xmx5000m makes ImageJ use 5GB of RAM, so this should be more than enough.
(taken from ImageJDocu)