Thumbnail Caching

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As of version 2.5.0, if you have an SD card installed multiFEED can cache thumbnail images once they have been downloaded. Prior to this version, the image files used to create thumbnails were always downloaded again each time a feed was refreshed. Although they were converted to a much smaller format internally, if you had Embedded Thumbnail conversion turned on this could have meant several megabytes downloaded for each thumbnail with every refresh. For this reason it was recommended that this feature be configured for WiFi only. Now that downloaded thumbnails are cached you may wish to change embedded thumbnail conversion to "Always" since data usage is hugely reduced from earlier versions of multiFEED. Use the resource monitoring on your Blackberry 10 device and the limits on your carrier data plan to determine if data usage is reduced enough to make it practical to enable embedded thumbnail conversion when Internet access is via your carrier network.

Thumbnail caching trades SD card storage space for data usage. Even though images are reduced from the original image size down to 320x180 before caching, if you follow a lot of feeds the thumbnail cache may take up several tens of megabytes on your storage card. For instance, in a sample configuration following 40 thumbnail-rich feeds with 740 cached images, the multiFEED thumbnail cache used just over 85Mb of SD card storage. To minimize resource usage cached thumbnails are only retained for three days after the last time they are used on the front page. After that they are purged to reclaim storage space. If you follow a large number of feeds thumbnail caching may result in a fairly high number of writes to flash memory. Flash storage supports a large but finite number of write cycles, so even though damage to your device storage is extremely unlikely, multiFEED only caches thumbnails if you have an SD card installed that it can use for the cache database. This way there is no danger of wearing out the built-in flash memory on your device.

If you enable this feature, the cache will be located at /multiFEED/thumbnailCache.db on your SD card.

Note that once it has been cached a thumbnail will always be displayed on the front page until purged from the cache even if you have thumbnails set to WiFi Only and you leave WiFi coverage. This is because unlike previous versions of multiFEED there is no data usage hit from displaying the image once it has been cached.