Gets the bits per component: 1 for an image mask, the dictionary's value otherwise; 0 when it is missing or unusable, and for a JPEG 2000 image that does not state it (the codestream decides).
public int BitsPerComponent { get; }
ISO 32000-2 §8.9.5.1, Table 87: 1, 2, 4, 8 or (PDF 1.5) 16. Other depths up to 16 are read, with a diagnostic, as other readers do; the samples are then stored at the next wider depth (StorageBits).