The image metadata is going to be read (see IImageInfo). This is not an actual flag because image metadata always needs to be read.
The image metadata and pixel data is going to be read (see IImageReader.ReadScanline).
Geo-referencing metadata (if present) is going to be read (see IGeorefInfo).
If necessary, builds the range of raw pixel values that are present in the image data (see IImageInfo.Values).
If the range of raw pixel values is already present in the header information of an image, this flag will have no effect. Otherwise, it will trigger an additional pass over the image data, in order to determine the raw pixel value range (see IImageReader.ReadValuesAll).