I've had this problem for maybe a couple of months, could be more or less, I wasn't keeping track.

XnView is slow to start first time I double click an image. After showing that image and then closing XNView, the next image shows almost immediately. However, if I don't view an image for some time, then next time XNView is slow to start again. I use Total Commander as my file manager, though that has never been an issue. My AV/Firewall is Comodo, which I initially suspected, but now I am not so sure. Not much to go on, I know, but any suggestions? I moved to XNView from IrfanView because I found it faster, but at the moment it is far from being fast.
Latest XNView, Win 7 Pro x86 SP1