 attempt to deduce the originating software
based only on the JPEG image data.  For performance reasons, this tag is
generated only if specifically requested)</span></span></td></tr>
<tr class=b>
<td>JPEGQualityEstimate</td>
<td class=c>N</td>
<td class=c>File</td>
<td><span class=s><span class=n>(an estimate of the IJG JPEG quality setting for the image, calculated from
the quantization tables.  For performance reasons, this tag is generated
only if specifically requested)</span></span></td></tr>
<tr>
<td>