How to change Moodle icons in file picker?

Question

Summary I need to replace the Moodle icons in the Moodle file picker with custom icons. I'm referring to the icons that appear in the File Picker window next to "Content Bank" "Server Files" "Recent Files" and "Private Files". (See screenshot below)

screenshot of file picker with Moodle icons

When I pull the URL for the image I get this file path: website.com/theme/image.php/trema/repository_contentbank/1601324857/icon

I can't seem to figure this file path out in order to replace the Moodle icon image. Does anyone know how to do this?

What I've Tried I've already replaced all of the png and svg Moodle icon files in the "pix" folders. No dice.

I've sifted through the "repository" folder, the "contentbank" folder and any other subfolder I could find but no luck.

I've also looked at the theme/image.php to look for instances where I can replace the file name but I can't figure it out. I'm posting the code for that file below.

Code Here's the theme/image.php code...

define('NO_DEBUG_DISPLAY', true);

// we need just the values from config.php and minlib.php
define('ABORT_AFTER_CONFIG', true);
require('../config.php'); // this stops immediately at the beginning of lib/setup.php

if ($slashargument = min_get_slash_argument()) {
    $slashargument = ltrim($slashargument, '/');
    if (substr_count($slashargument, '/') < 3) {
        image_not_found();
    }
    if (strpos($slashargument, '_s/') === 0) {
        // Can't use SVG
        $slashargument = substr($slashargument, 3);
        $usesvg = false;
    } else {
        $usesvg = true;
    }
    // image must be last because it may contain "/"
    list($themename, $component, $rev, $image) = explode('/', $slashargument, 4);
    $themename = min_clean_param($themename, 'SAFEDIR');
    $component = min_clean_param($component, 'SAFEDIR');
    $rev       = min_clean_param($rev, 'INT');
    $image     = min_clean_param($image, 'SAFEPATH');

} else {
    $themename = min_optional_param('theme', 'standard', 'SAFEDIR');
    $component = min_optional_param('component', 'core', 'SAFEDIR');
    $rev       = min_optional_param('rev', -1, 'INT');
    $image     = min_optional_param('image', '', 'SAFEPATH');
    $usesvg    = (bool)min_optional_param('svg', '1', 'INT');
}

if (empty($component) or $component === 'moodle' or $component === 'core') {
    $component = 'core';
}

if (empty($image)) {
    image_not_found();
}

if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
    // exists
} else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$themename/config.php")) {
    // exists
} else {
    image_not_found();
}

$candidatelocation = "$CFG->localcachedir/theme/$rev/$themename/pix/$component";
$etag = sha1("$rev/$themename/$component/$image");

if ($rev > 0) {
    if (file_exists("$candidatelocation/$image.error")) {
        // This is a major speedup if there are multiple missing images,
        // the only problem is that random requests may pollute our cache.
        image_not_found();
    }
    $cacheimage = false;
    if ($usesvg && file_exists("$candidatelocation/$image.svg")) {
        $cacheimage = "$candidatelocation/$image.svg";
        $ext = 'svg';
    } else if (file_exists("$candidatelocation/$image.png")) {
        $cacheimage = "$candidatelocation/$image.png";
        $ext = 'png';
    } else if (file_exists("$candidatelocation/$image.gif")) {
        $cacheimage = "$candidatelocation/$image.gif";
        $ext = 'gif';
    } else if (file_exists("$candidatelocation/$image.jpg")) {
        $cacheimage = "$candidatelocation/$image.jpg";
        $ext = 'jpg';
    } else if (file_exists("$candidatelocation/$image.jpeg")) {
        $cacheimage = "$candidatelocation/$image.jpeg";
        $ext = 'jpeg';
    } else if (file_exists("$candidatelocation/$image.ico")) {
        $cacheimage = "$candidatelocation/$image.ico";
        $ext = 'ico';
    }
    if ($cacheimage) {
        if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
            // We do not actually need to verify the etag value because our files
            // never change in cache because we increment the rev parameter.
            // 90 days only - based on Moodle point release cadence being every 3 months.
            $lifetime = 60 * 60 * 24 * 90;
            $mimetype = get_contenttype_from_ext($ext);
            header('HTTP/1.1 304 Not Modified');
            header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
            header('Cache-Control: public, max-age='.$lifetime.', no-transform');
            header('Content-Type: '.$mimetype);
            header('Etag: "'.$etag.'"');
            die;
        }
        send_cached_image($cacheimage, $etag);
    }
}

//=================================================================================
// ok, now we need to start normal moodle script, we need to load all libs and $DB
define('ABORT_AFTER_CONFIG_CANCEL', true);

define('NO_MOODLE_COOKIES', true); // Session not used here
define('NO_UPGRADE_CHECK', true);  // Ignore upgrade check

require("$CFG->dirroot/lib/setup.php");

$theme = theme_config::load($themename);
$themerev = theme_get_revision();

if ($themerev <= 0 or $rev != $themerev) {
    // Do not send caching headers if they do not request current revision,
    // we do not want to pollute browser caches with outdated images.
    $imagefile = $theme->resolve_image_location($image, $component, $usesvg);
    if (empty($imagefile) or !is_readable($imagefile)) {
        image_not_found();
    }
    send_uncached_image($imagefile);
}

make_localcache_directory('theme', false);

// At this stage caching is enabled, and either:
// * we have no cached copy of the image in any format (either SVG, or non-SVG); or
// * we have a cached copy of the SVG, but the non-SVG was requested by the browser.
//
// Because of the way in which the cache return code works above:
// * if we are allowed to return SVG, we do not need to cache the non-SVG version; however
// * if the browser has requested the non-SVG version, we *must* cache _both_ the SVG, and the non-SVG versions.

// First get all copies - including, potentially, the SVG version.
$imagefile = $theme->resolve_image_location($image, $component, true);

if (empty($imagefile) || !is_readable($imagefile)) {
    // Unable to find a copy of the image file in any format.
    // We write a .error file for the image now - this will be used above when searching for cached copies to prevent
    // trying to find the image in the future.
    if (!file_exists($candidatelocation)) {
        @mkdir($candidatelocation, $CFG->directorypermissions, true);
    }
    // Make note we can not find this file.
    $cacheimage = "$candidatelocation/$image.error";
    $fp = fopen($cacheimage, 'w');
    fclose($fp);
    image_not_found();
}

// The image was found, and it is readable.
$pathinfo = pathinfo($imagefile);

// Attempt to cache it if necessary.
// We don't really want to overwrite any existing cache items just for the sake of it.
$cacheimage = "$candidatelocation/$image.{$pathinfo['extension']}";
if (!file_exists($cacheimage)) {
    // We don't already hold a cached copy of this image. Cache it now.
    $cacheimage = cache_image($image, $imagefile, $candidatelocation);
}

if (!$usesvg && $pathinfo['extension'] === 'svg') {
    // The browser has requested that a non-SVG version be returned.
    // The version found so far is the SVG version - try and find the non-SVG version.
    $imagefile = $theme->resolve_image_location($image, $component, false);
    if (empty($imagefile) || !is_readable($imagefile)) {
        // A non-SVG file could not be found at all.
        // The browser has requested a non-SVG version, so we must return image_not_found().
        // We must *not* write an .error file because the SVG is available.
        image_not_found();
    }

    // An non-SVG version of image was found - cache it.
    // This will be used below in the image serving code.
    $cacheimage = cache_image($image, $imagefile, $candidatelocation);
}

if (connection_aborted()) {
    // Request was cancelled - do not send anything.
    die;
}

// Make sure nothing failed.
clearstatcache();
if (file_exists($cacheimage)) {
    // The cached copy was found, and is accessible. Serve it.
    send_cached_image($cacheimage, $etag);
}

send_uncached_image($imagefile);

//=================================================================================
//=== utility functions ==
// we are not using filelib because we need to fine tune all header
// parameters to get the best performance.

function send_cached_image($imagepath, $etag) {
    global $CFG;
    require("$CFG->dirroot/lib/xsendfilelib.php");

    // 90 days only - based on Moodle point release cadence being every 3 months.
    $lifetime = 60 * 60 * 24 * 90;
    $pathinfo = pathinfo($imagepath);
    $imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];

    $mimetype = get_contenttype_from_ext($pathinfo['extension']);

    header('Etag: "'.$etag.'"');
    header('Content-Disposition: inline; filename="'.$imagename.'"');
    header('Last-Modified: '. gmdate('D, d M Y H:i:s', filemtime($imagepath)) .' GMT');
    header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
    header('Pragma: ');
    header('Cache-Control: public, max-age='.$lifetime.', no-transform, immutable');
    header('Accept-Ranges: none');
    header('Content-Type: '.$mimetype);

    if (xsendfile($imagepath)) {
        die;
    }

    if ($mimetype === 'image/svg+xml') {
        // SVG format is a text file. So we can compress SVG files.
        if (!min_enable_zlib_compression()) {
            header('Content-Length: '.filesize($imagepath));
        }
    } else {
        // No need to compress other image formats.
        header('Content-Length: '.filesize($imagepath));
    }

    readfile($imagepath);
    die;
}

function send_uncached_image($imagepath) {
    $pathinfo = pathinfo($imagepath);
    $imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];

    $mimetype = get_contenttype_from_ext($pathinfo['extension']);

    header('Content-Disposition: inline; filename="'.$imagename.'"');
    header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
    header('Expires: '. gmdate('D, d M Y H:i:s', time() + 15) .' GMT');
    header('Pragma: ');
    header('Accept-Ranges: none');
    header('Content-Type: '.$mimetype);
    header('Content-Length: '.filesize($imagepath));

    readfile($imagepath);
    die;
}

function image_not_found() {
    header('HTTP/1.0 404 not found');
    die('Image was not found, sorry.');
}

function get_contenttype_from_ext($ext) {
    switch ($ext) {
        case 'svg':
            return 'image/svg+xml';
        case 'png':
            return 'image/png';
        case 'gif':
            return 'image/gif';
        case 'jpg':
        case 'jpeg':
            return 'image/jpeg';
        case 'ico':
            return 'image/vnd.microsoft.icon';
    }
    return 'document/unknown';
}

/**
 * Caches a given image file.
 *
 * @param string $image The name of the image that was requested.
 * @param string $imagefile The location of the image file we want to cache.
 * @param string $candidatelocation The location to cache it in.
 * @return string The path to the cached image.
 */
function cache_image($image, $imagefile, $candidatelocation) {
    global $CFG;
    $pathinfo = pathinfo($imagefile);
    $cacheimage = "$candidatelocation/$image.".$pathinfo['extension'];

    clearstatcache();
    if (!file_exists(dirname($cacheimage))) {
        @mkdir(dirname($cacheimage), $CFG->directorypermissions, true);
    }

    // Prevent serving of incomplete file from concurrent request,
    // the rename() should be more atomic than copy().
    ignore_user_abort(true);
    if (@copy($imagefile, $cacheimage.'.tmp')) {
        rename($cacheimage.'.tmp', $cacheimage);
        @chmod($cacheimage, $CFG->filepermissions);
        @unlink($cacheimage.'.tmp'); // just in case anything fails
    }
    return $cacheimage;
}

Answer 1

Maybe try enable "Theme designer mode" HOME -> SITE ADMINISTRATION -> APPEARANCE -> THEMES -> THEME SETTINGS and purge caches.