lseek (file_id, headersize, SEEK_SET);
T pixelBuffer;
for (int ix = 0; ix < mNX; ix++)
for (unsigned int iy = 0; iy < mNY; iy++) {
read (file_id, &pixelBuffer, mPixelSize);
lseek (file_id, headersize, SEEK_SET);
T pixelBuffer;
for (int ix = 0; ix < mNX; ix++)
for (unsigned int iy = 0; iy < mNY; iy++) {
read (file_id, &pixelBuffer, mPixelSize);