if d.img1 == nil && d.img3 == nil {
		d.makeImg(mxx, myy)
	}
	if d.progressive {
		for i := 0; i < nComp; i++ {
			compIndex := scan[i].compIndex
			if d.progCoeffs[compIndex] == nil {
				d.progCoeffs[compIndex] = make([]block, mxx*myy*d.comp[compIndex].h*d.comp[compIndex].v)
			}
		}
	}

	d.bits = bits{}
	mcu, expectedRST := 0, uint8(rst0Marker)
	var (

	jfif                bool
	adobeTransformValid bool
	adobeTransform      uint8
	eobRun              uint16 // End-of-Band run, specified in section G.1.2.2.

	comp       [maxComponents]component
	progCoeffs [maxComponents][]block // Saved state between progressive-mode scans.
	huff       [maxTc + 1][maxTh + 1]huffman
	quant      [maxTq + 1]block // Quantization tables, in zig-zag order.
	tmp        [2 * blockSize]byte
}