Reduce number of colors (unique combinations of R,G,B) in your images. The tools first calculates best colors than converts the image to them.
This is gimp plugin and in addition to reducing colors it denoise ("defragments") the output image and creates lines between areas of different colors.
See Wiki page with introduction and examples
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001291s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.102939s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001178s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001927s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001184s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.005651s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001544s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.006292s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.017362s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001409s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 283950 [ RunTime:0.001441s ]
