????? ??????????(δ????)
????????????????????CGI?????????????????????y?塣?????????????MIME?????п??м?????????ɡ?
??????image.cgi????????GIF?????????????????????
#!/usr/bin/perl
$file = '/usr/local/etc/httpd/htdocs/images/picture.gif';
print "Content-Type: image/gif\n\n";
open(GIF,"<$file") || die "Can't open GIF\n";
while (read(GIF,$buffer,16384)) {
print $buffer;
}
image.cgi???????MIME????(Content-Type)??????????????????????γ????$file??????Content-Type??????????????????????????????
?????????CGI??????????????????????SSI????е??????????<img>????????磺
<img src="/cgi-bin/image.cgi">
???????picture.gif??????????????????image.cgi????????????????????????????????
<img src="/images/picture.gif">
?????image.cgi?????????????????????????????????????????????漴???????????????????????η??????????????????????
?????????????????<img>?????????????????????Щ?????????HTML??SSI????????????á??????????????HTML?????????????????????
?????????????????????е????????????????????????????????????????????CGI?????????????????????????Щ???????????????????????????????????????????????????????????????????????????????????????????Щ?????????????????Thomas boutell??gd????????????GIF????????????????????http://www.boutell.com/gd?????????????C????д?????????Perl????gd.pm?????л???gd??????????????tgd??fly??????????????gd?????
???????????????λ?????????????????????????????????????????????????????????????
????GIF?????
???????????????????????GIF?????????Portable Network Graphic???(PNG)??????仯?????????????????????????1995??1??1???Unisys?????????????????LZW?????????????????????????????????????????????????????????GIF?????????????????????????????д???κ??????????ó????е?GIF?????????CGI/WWW?????????Щ???????????????????????????á????????????????GIF????????????????ú?????????GIF????????????????????PNG??÷????????????????????????Щ?鷳??????????棬PNG???????????????????????GIF???????????JPEG??JPEG??????????????????????????24λ??48λ??????????????????????????????PNG??????????????????????????????GD??ο?????????PNG???????????
????? ??
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