if convert "$X" -depth 16 RGBA:- | perl -e 'while(read STDIN, $_, 8) { substr($_, 6, 2) eq "\xFF\xFF" or exit 1; ++$pix; } exit not $pix;'; then
echo "$X has no alpha, converting"
convert "$X" -quality 100 "${X%.*}.jpg"
if convert "$X" -depth 16 RGBA:- | perl -e 'while(read STDIN, $_, 8) { substr($_, 6, 2) eq "\xFF\xFF" or exit 1; ++$pix; } exit not $pix;'; then
echo "$X has no alpha, converting"
convert "$X" -quality 100 "${X%.*}.jpg"
echo "$X has alpha, converting twice"
convert "$X" -alpha extract -quality 100 "${X%.*}.jpg"
convert "$X" -alpha off -quality 100 "${X%.*}_alpha.jpg"
echo "$X has alpha, converting twice"
convert "$X" -alpha extract -quality 100 "${X%.*}.jpg"
convert "$X" -alpha off -quality 100 "${X%.*}_alpha.jpg"