public BitmapSize EffectTileSize { get; set; }

Property Value

For advanced scenarios, this property allows the application to tune the performance and resource usage of effect drawing operations.

Large image effects are drawn by splitting them up into a number of smaller tiles, which are sent separately to the GPU. This reduces intermediate memory usage, and allows processing very large images (potentially larger than MaximumBitmapSizeInPixels, which can be necessary for instance during printing).

The default tile size is 1024x1024.

Reference