The behaviour of imread depends on the specific implementation, but in general, it is possible for the function to download and extract a specific region of interest without downloading the entire image.
In the case of Cloud Optimized GeoTIFFs (COGs), the file format is designed specifically to allow efficient access to specific regions of interest without requiring the entire image to be downloaded. COGs are organized into small, tiled files that can be accessed independently, allowing for selective download and processing.
When using imread with the 'PixelRegion' option, it should request only the necessary tiles to cover the specified region of interest, rather than downloading the entire image. This can significantly reduce download times, especially for large images.
