Image Downloader (Blocking) is an alternative to the built-in "Image Downloader" patch, and is distinct in the following ways:
It blocks rendering until the image is loaded (unlike the built-in patch, which continues rendering, but the image may not appear until many frames have rendered)
It has a user-definable VRAM cache limit. Do a "Show Package Contents" on the patch bundle, edit the Info.plist, and check out the ImageDownloaderBlockingCacheVRAMLimitPercent property. It's a decimal scalar percent; "0.75" means "use 75% of available texture ram on the active display context".