Gets or sets the most bytes of decoded images (image XObjects with their masks, soft masks and colour tables, and stencil masks) a document keeps for its next display lists; the least recently used are dropped beyond it and decoded again when painted. An image larger than the budget is decoded for each list that paints it. Zero keeps none: each list decodes its own. Default 64 MiB.
public long ImageCacheBudget { get; set; }
Spec #33 viewer capability 13; ISO 32000-2 §8.9.5 (image XObjects), §8.9.6 and §11.6.5 (masks). Observed through CacheStatistics (Images). A display list holds the images it paints whatever this budget, so a list kept by the caller keeps its images alive after they leave the cache.