{"id":69351,"date":"2025-08-05T03:01:00","date_gmt":"2025-08-04T17:01:00","guid":{"rendered":"https:\/\/www.rjmprogramming.com.au\/ITblog\/?p=69351"},"modified":"2025-08-05T07:40:27","modified_gmt":"2025-08-04T21:40:27","slug":"command-line-imagemagick-jpeg-image-creation-tutorial","status":"publish","type":"post","link":"https:\/\/www.rjmprogramming.com.au\/ITblog\/command-line-imagemagick-jpeg-image-creation-tutorial\/","title":{"rendered":"Command Line ImageMagick JPEG Image Creation Tutorial"},"content":{"rendered":"<div style=\"width: 230px\" class=\"wp-caption alignnone\"><a target=\"_blank\" href=\"http:\/\/www.rjmprogramming.com.au\/Mac\/paintbrush_crontab_png_to_jpeg.gif\" rel=\"noopener\"><img decoding=\"async\" style=\"border: 15px solid pink;\" alt=\"Command Line ImageMagick JPEG Image Creation Tutorial\" src=\"http:\/\/www.rjmprogramming.com.au\/Mac\/paintbrush_crontab_png_to_jpeg.gif\" title=\"Command Line ImageMagick JPEG Image Creation Tutorial\"  style=\"float:left;\"  \/><\/a><p class=\"wp-caption-text\">Command Line ImageMagick JPEG Image Creation Tutorial<\/p><\/div>\n<p>For a while now, on macOS, we&#8217;ve been putting up with a scenario with our beloved macOS <a target=\"_blank\" title='macOS PaintBrush' href='https:\/\/paintbrush.sourceforge.io\/' rel=\"noopener\">Paintbrush<\/a> desktop application version whereby it will not save images in &#8230;<\/p>\n<ul>\n<li>JPEG format &#8230; any more, so we have been saving in &#8230;<\/li>\n<li>PNG format<\/li>\n<\/ul>\n<p> &#8230; for some time now.  Is this a big deal?  Well, that is the question?  We got a bit of a surprise in aspects of the solution we came up with.<\/p>\n<p>With that, pretty obvious to us, first aim of smaller sized output image media files to start producing, we decided to involve &#8230;<\/p>\n<ul>\n<li>macOS command line &#8230;<\/li>\n<li>PHP usage ( ending up with <a target=\"_blank\" href=\"http:\/\/www.rjmprogramming.com.au\/Mac\/paintbrush_png_jpg.php_GETME\" rel=\"noopener\">paintbrush_png_jpg.php<\/a> ) &#8230; in a &#8230;<\/li>\n<li><a target=\"_blank\" title='crontab information from computerhope ... thanks' href='http:\/\/www.computerhope.com\/jargon\/c\/cron.htm' rel=\"noopener\">crontab<\/a> scheduled &#8230;<br \/>\n<code><br \/>\n* * * * * ksh -c \"cd \/Applications\/MAMP\/htdocs; \/Applications\/MAMP\/bin\/php\/php7.4.33\/bin\/php \/Applications\/MAMP\/htdocs\/paintbrush_png_jpg.php\"<br \/>\n<\/code>\n<\/li>\n<\/ul>\n<p> &#8230; procedure, running each minute here on this MacBook Air using a command line command exemplified for a PNG called my_image.png &#8230;<\/p>\n<p><code><br \/>\n <a target=\"_blank\" title='ImageMagick software suite' href='https:\/\/www.imagemagick.org\/' rel=\"noopener\">convert<\/a> -quality 30 my_image.png my_image.jpeg<br \/>\n<\/code><\/p>\n<p> &#8230; via this PHP ( where we thank <a target=\"_blank\" title='Useful link, thanks' href='https:\/\/stackoverflow.com\/questions\/13324277\/select-a-file-that-was-created-the-last-minute' rel=\"noopener\">this useful link<\/a> for great help ) &#8230;<\/p>\n<p><code><br \/>\n&lt;?php<br \/>\n  \/\/ paintbrush_png_jpg.php<br \/>\n  \/\/ August, 2025<br \/>\n  \/\/ crontab php command line called way to backup Paintbrush created *.png to reduced size *.jpg<br \/>\n  $it = new GlobIterator(__DIR__ . \"\/*.png\");<br \/>\n  $last2mis = 9020;<br \/>\n  foreach ( $it as $file ) {<br \/>\n    if ((time() - $file-&gt;getMTime()) &lt;= $last2mis) {<br \/>\n      if (!file_exists(str_replace('.png','.jpg',$file)) && !file_exists(str_replace('.png','.jpeg',$file))) {<br \/>\n        exec(\"cd \" . __DIR__ . '; \/usr\/local\/bin\/convert -quality 30 ' . $file . ' ' . str_replace('.png','.jpeg',$file));<br \/>\n      }<br \/>\n    }<br \/>\n  }<br \/>\n?&gt;<br \/>\n<\/code><\/p>\n<p> &#8230; which achieves it&#8217;s objective, for the most part, because we are always saving these PNG files to <a target=\"_blank\" title='MAMP for Apache\/PHP\/MySql on Mac OS X local web server' href='http:\/\/www.mamp.info' rel=\"noopener\">MAMP<\/a>&#8216;s Document Root ( ie. \/Applications\/MAMP\/htdocs for us ).<\/p>\n<p>All good, smaller image JPEG files do result, but the twist for us came when we assembled our first JPEG vs PNG sets &#8230;<\/p>\n<p><code><br \/>\n$ ls -l mamp_p*.*g*<br \/>\n-rw-r--r--  1 user  admin   459400  3 Aug 15:15 mamp_paintbrush_job-15.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  1857056  3 Aug 14:39 mamp_paintbrush_job-15.png<br \/>\n-rw-r--r--  1 user  admin   413477  3 Aug 15:14 mamp_paintbrush_job-17.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  1816410  3 Aug 14:47 mamp_paintbrush_job-17.png<br \/>\n-rw-r--r--@ 1 user  admin   246569  3 Aug 15:08 mamp_paintbrush_job-21.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  1959028  3 Aug 15:08 mamp_paintbrush_job-21.png<br \/>\n-rw-r--r--  1 user  admin   264874  3 Aug 15:10 mamp_paintbrush_job-23.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  2555260  3 Aug 15:09 mamp_paintbrush_job-23.png<br \/>\n-rw-r--r--  1 user  admin   249117  3 Aug 15:11 mamp_paintbrush_job-25.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  2704233  3 Aug 15:11 mamp_paintbrush_job-25.png<br \/>\n-rw-r--r--  1 user  admin   230524  3 Aug 15:16 mamp_paintbrush_job-27.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  1962296  3 Aug 15:15 mamp_paintbrush_job-27.png<br \/>\n-rw-r--r--  1 user  admin   280417  3 Aug 15:17 mamp_paintbrush_job-29.jpeg<br \/>\n-rw-r--r--@ 1 user  admin  2677561  3 Aug 15:16 mamp_paintbrush_job-29.png<br \/>\n$<br \/>\n<\/code><\/p>\n<p> &#8230; into two animated GIF images ( with PNG based one called paintbrush_crontab_png_to_jpeg.gif ) &#8230;<\/p>\n<p><code><br \/>\n$ ls -l paintbrush_*.gif<br \/>\n-rw-r--r--@ 1 user  staff  5100166  3 Aug 19:11 <a target=\"_blank\" href=\"http:\/\/www.rjmprogramming.com.au\/Mac\/paintbrush_crontab_png_to_jpeg.gif\" rel=\"noopener\">paintbrush_crontab_png_to_jpeg.gif<\/a><br \/>\n-rw-r--r--@ 1 user  staff  6485830  3 Aug 19:14 <a target=\"_blank\" href=\"http:\/\/www.rjmprogramming.com.au\/Mac\/paintbrush_png_to_jpeg_crontab.gif\" rel=\"noopener\">paintbrush_png_to_jpeg_crontab.gif<\/a><br \/>\n$<br \/>\n<\/code><\/p>\n<p> &#8230; via our inhouse <a target=\"_blank\" href='http:\/\/www.rjmprogramming.com.au\/PHP\/animegif\/tutorial_to_animated_gif.php' rel=\"noopener\">animated GIF creator helper<\/a> web application.<\/p>\n<p><a target=\"_blank\" title='animated GIF larger creating it with JPEG than PNG' href='https:\/\/www.google.com\/search?q=animated+GIF+larger+creating+it+with+JPEG+than+PNG&#038;rlz=1C5OZZY_en&#038;oq=animated+GIF+larger+creating+it+with+JPEG+than+PNG&#038;gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigAdIBCjI3NzgzajBqMTWoAgiwAgHxBTV7r9iyF30D&#038;sourceid=chrome&#038;ie=UTF-8' rel=\"noopener\">Huh?!<\/a>   Read a <a target=\"_blank\" title='Is it better to make a GIF out of a JPG or PNG?' href='https:\/\/graphicdesign.stackexchange.com\/questions\/159310\/is-it-better-to-make-a-gif-out-of-a-jpg-or-png' rel=\"noopener\">bit more about it here<\/a>!<\/p>\n<p>If this was interesting you may be interested in <a title='Click here to see topics in which you might be interested' href='#d69351' onclick='var dv=document.getElementById(\"d69351\"); dv.innerHTML = \"&lt;iframe width=670 height=600 src=\" + \"https:\/\/www.rjmprogramming.com.au\/ITblog\/tag\/animated-GIF\" + \"&gt;&lt;\/iframe&gt;\"; dv.style.display = \"block\";'>this<\/a> too.<\/p>\n<div id='d69351' style='display: none; border-left: 2px solid green; border-top: 2px solid green;'><\/div>\n","protected":false},"excerpt":{"rendered":"<p>For a while now, on macOS, we&#8217;ve been putting up with a scenario with our beloved macOS Paintbrush desktop application version whereby it will not save images in &#8230; JPEG format &#8230; any more, so we have been saving in &hellip; <a href=\"https:\/\/www.rjmprogramming.com.au\/ITblog\/command-line-imagemagick-jpeg-image-creation-tutorial\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,29,37],"tags":[96,233,234,274,319,1793,590,1658,662,896,932,2042,997,5264,1319],"class_list":["post-69351","post","type-post","status-publish","format-standard","hentry","category-elearning","category-operating-system","category-tutorials","tag-application","tag-command","tag-command-line","tag-crontab","tag-desktop","tag-format","tag-image","tag-imagemagick","tag-jpeg","tag-paintbrush","tag-php","tag-png","tag-programming","tag-talents","tag-tutorial"],"_links":{"self":[{"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/posts\/69351"}],"collection":[{"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/comments?post=69351"}],"version-history":[{"count":8,"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/posts\/69351\/revisions"}],"predecessor-version":[{"id":69361,"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/posts\/69351\/revisions\/69361"}],"wp:attachment":[{"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/media?parent=69351"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/categories?post=69351"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rjmprogramming.com.au\/ITblog\/wp-json\/wp\/v2\/tags?post=69351"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}