imageCacheBudgetBytes

The most bytes of decoded images that this document keeps, so that an image drawn again, on another page or at another zoom, does not decode again. The image used least recently leaves first, and an image larger than the whole budget is not kept. The default is DEFAULT_IMAGE_CACHE_BUDGET_BYTES; 0 keeps no image. Lower it for a small heap, and call dropDecodedImageCache when the app runs low on memory.