OziExplorerCE only supports the image formats ozfx3, ozf2, ecw, .jpg, .png and .bmp. Ozfx3 and ozf2 were especially developed for use in OziExplorerCE.
The image formats jpg, png and bmp are fully loaded into memory so the images must be small and only 8bit and 24bit color formats are supported.
A conversion program is provided to convert map images into ozfx3 format. Most of the file formats supported by PC OziExplorer can be converted. It is highly recommended maps in jpg, png and bmp format are converted to OZFx3 using the Img2Ozf conversion software.
(Note: Because the code libraries available only suit the ARM cpu the ECW support is only available for PDA's with ARM cpu's.)
The ECW format is highly compressed and therefore it takes longer to uncompress the piece of image required and this makes it slower to use than the ozfx3 format.
The OZF2 format has been superseded by the OZFx3 format and can no longer be created by the Img2ozf conversion software.
Why a New Format?
The PocketPC and CE devices with limited RAM require an image format which can be read from disk as required, that is, just the portion needed to be displayed on the screen can be read from the file (this is called paging), this keeps the memory requirements of the software very low. The OZFx3 format was developed to allow very fast paging from disk. ECW is also a paging format but due to its high compression, the ECW format is a slower format to load on a PDA than OZFx3.
The BMP, JPG and PNG formats cannot be "paged" from disk (generally) so the entire image must be read and stored in memory. This means 2 copies of the image are needed when the image is loaded, 1 on file and 1 in memory. CE devices usually do not have enough memory to allow this for reasonable sized maps. To use these formats, the map images must be small. It is highly recommended maps in jpg, png and bmp format are converted to OZFx3 using the Img2Ozf conversion software.
In some cases the size of the image stored on a plug in memory card may exceed the device's program memory, because the ozfx3 format is paged from disk the software can still load and use the large image.
There is no upper limit on the size of an ozfx3 image file, the limit is the ability to convert the image
OZF Conversion Software