FastPictureViewer is the meanest, leanest, smallest image viewer in existence, period. The program weights about 1 MB on disk and consumes approximately 8 MB of memory for its own use, everything else being image data.
In order to improve viewing speed, FPV uses a number of advanced tricks, one of them being to preload and cache images in advance, so the next one is always ready when you want to move on in the image list.
The program actually use an adaptive algorithm to decide if it can preload images, how many of them, and for how long it can keep them in memory, depending on available resources. This processus is entirely automatic and enabled by default, but it is possible to influence the decisions taken by the program, namely to disable preloading altogether, or hint the program at preload more (or less) images in memory.
Depending on your work habits (how many apps you use concurrently in your workflow), the available physical ressources such as video memory or central memory and the size of your images, you can influence the program's behavior regarding memory consumption, from the absolute minimal resource usage to maximum memory consumption (for maximum speed).
See Menu->Options->Resource Usage to configure the program's behavior in this respect. You can also enable parallel image loading for even faster image loading on multi-core machines, for the absolute quickest possible viewing experience.
The program ships with reasonable defaults but it's worth trying to tweak the settings a little, to perhaps better fit your requirements and available computer resources.
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