The ImageGear ASP.NET web.config parameter cachingTimeLimit specifies the number of minutes that a document will remain stored in the ASP.NET cache storage from the last time it was accessed. If the document is not accessed within the allotted time, it will be removed from the cache. The entire document must meet the constraints specified by the maxImageSizeToCache parameter (specified in kilobytes) in order to be cached. Otherwise, the document will not be placed into the cache. Of course, the parameter cachingEnable needs to be set to "true" to enable the ASP.NET caching mechanism.

The cached document will be accessed more quickly than one stored in a storage media device and is used even for tile formation of raster images. Raster tiles give better image fidelity than a scaled full-size image page. Depending on the original document size and requested zoom-in image, 2 or more tiles may be needed to pan around the document page by the browser application viewing the document page. So enabling the cache helps for a faster viewing experience. Of course, tiles are not required for documents that can be converted to SVG format by the ImageGear ASP.NET product. The SVG format is scalable by the web browser client viewer.

The only other aspect of caching with the ImageGear ASP.NET product is the user agent or browser caching. The ImageGear ASP.NET product requests a short time frame of approximately 20 seconds to the browser to hold onto the viewed document. Subsequent requests by the browser will most likely participate on a round-trip request for the page if the same page is refreshed. The short duration prevents possible quick redundant requests from downloading the document page unnecessarily.

See Image Data Provider Configuration section on setting these cache parameters in the web.config file.