Direct install from this site is not allowed in current version of Firefox. You need to do a manual install from file by download the file (xpi type file) to your computer. Usually download the file from mirror site is work. Then open Firefox. Open the Add-on Manager by press Shift-Control-A (or type about:addons at URL bar). Click the "Tool for all add-ons" icon (Gear icon).,Click the "Install Add-on from file...". And choose the downloaded xpi file.
Right click at your bookmark (Bookmark menu, Bookmark toolbar, Bookmark sidebar, Bookmark manager); the popup menu with option "Change Favicon", "Reset Favicon", "Remove Favicon" and "Export Favicon" will appear.
File types support are ico, bmp, dib, gif, jpg, jpe, jpeg, jif, jfi, jfif, png, apng, svg (every file types that Firefox or SeaMonkey support including URL).
Support every size of image file. There is no different in disk space requirement between big and small image size. Every image will be resized and changed to 16x16 pixels png files and saved.
After changing favicon, there is no need for that favicon file to exist again.
Bookmark folder, Livemark container and livemark item favicon can be changed too! (Note that form Firefox version 13 and SeaMonkey version 2.10, you cannot chage favicon of livemark item. Livemark item do not support favicon anymore and has only two icon stage: "not visited" and "visited").
After changing favicon, you can reset it back or remove it and use the default one.
Support bookmark favicon export. No matter what it is the original favicon or changed favicon.
[Optional] When you backup bookmark, you can embed favicon data in it (only JSON file format). So you can get these favicons back easily when restore bookmark.
Trustworthy because "Bookmark Favicon Changer" is the open source extension. You can check it by yourself that there is no backdoor or any harmful things inside.
This extension is designed for bookmark favicon only. Tab icon is not protected. You may see that tab icon is changed back, this is normal.
Animated favicon is not supported. Animated favicon will be changed to normal non-animated favicon and saved.
Only changing bookmark folder and livemark container favicon require bookmark sidebar and bookmark manager to reload. Reloading will be done automatically by my extension.
Bookmarks that have the same URL will have the same favicon. But folders that have the same label can have different favicon.
"Embed favicon data in JSON Bookmark backup file" can make backing up bookmark slower. This including automatic backup bookmark which is done at the idle or browser shutdown process. The other thing is you can restore these favicons back only when this extension is installed and active.
Due to custom favicons for bookmarks and folders are not standard, they are applied methods. So, the other add-ons that do bookmark synchronizing such as Firefox Sync, SeaMonkey Sync, Xmarks or FEBE may not understand this. They may not kind to your custom favicons and nothing I can do about this. The solution is to backup your favicon by enable "Embed favicon data in JSON Bookmark backup file" option or "export all custom favicons". This will help you by restore favicons back when something not right occur.
Mac OS X Only - "OS X Menu Bar" (topmost of the desktop) is the process outside Firefox and SeaMonkey, so it cannot be controlled effectively by my extension. Sometime you may notice that OS X Menu bar has a wrong favicon. Please see here for more detail.
Mac OS X Only - Firefox 9 and SeaMonkey 2.6 has a bug in menu. It do not show favicon. Please see this for more information.
Firefox Only - On rare occasion, you may experience Firefox freeze or slow down. This usually occur by damaged "Places database" which caused by improper Firefox shutdown or bug in Firefox upgrading process. Due to this add-on use an extensive bookmark access (which is store in "Places database"), this error symptom will appear more easier and more frequently. Please see this link and this link for more information to solve the problem.
Roomy Bookmarks Toolbar - Hides the names of the bookmarked links and shows you only their icons, so that you can visualize more of them at a time.
Identfavicon - Use identicons to automatically generate favicons for sites without one.
HashColouredTabs+ - Improves tab identification by providing a small colored icon for any site which doesn't have its own 'site icon'.
Q - Cannot install, only download happen. How can I do a manual install?
A - Sometime, click to install may not work. Instead of install, your browser just download it. If this happen, you need to do a manual install which can do in 3 ways.
Q - Is this add-on auto-update?
A - If you use version 2.10 or later, it will auto-update.
Q - Is this add-on signed by Mozilla?
A - Version 2.28 and later are signed.
Q - Why this add-on is not host on Mozilla?
Q - Is it better to have someone review this add-on before publishing like Mozilla do?
A - Seem like that. But if you know the truth about Mozilla reviewing process, you will be surprised. First, Reviewers are volunteers, which can be anyone including developer himself. Second, from my experience, reviewing process could take time from 10 seconds to 4 weeks. How could you trust reviewer who review add-on by using only 10 seconds? And how could you tolerate the bug fix version which released very late on the next month? If you don't believe me, you can see the example of "Add-ons Update Report" from Mozilla at here.
Q - You say it is open source. How can I read the source code?
A - Add-on itself is a source code. If you want to read it, you need to download the add-on first (usually by go to mirror site). You will get one "XPI" file which you can do a manual install (see above FAQ). But instead of install, you rename it to "ZIP" file. Then unzip it, you will get all of source codes.
Q - There is a link to website "bitly.com" in your source code. It look suspicious. Why?
A - It is for auto-update process. I need to download "RDF" file to check for latest version which is host on this site. I use "bitly.com" as an intermediate redirection site to get anonymous statistic. Bitly.com is a very free popular third party website, anyone can use it. Connection to bitly.com is also on a secure channel "SSL-HTTPS". This statistic is opened and public, you can see the statistic and target redirection URL at here. Please note that It is not just me that record anonymous statistic, Mozilla themselves also record anonymous statistic when add-on check for update.
Q - What license this add-on use? Can I modify or improve it?
A - This add-on is full copyright because I don't want to donate it to Mozilla. But don't worry, I allow you to do anything to my add-on, including edit, modified, publish, copy, distribute as long as it is free and you include my name for credit of creation of this add-on. The most important point of this copyright is "Don't donate it or part of it to Mozilla".
Q - Why is it free? Is it free forever? Are you making money from this extension?
A - It is free because I want to "make the world a better place". It will be free forever except if there is a gun pointed to my head (not literally, of course). And I do not make any money from this extension. I do not involve other websites that use my extension to promote their websites for other purposes, and I do not get paid.
Q - Can I donate to you? Can I help you in any other way?
A - No, I don't want any donation. If you want to help, just help other non-profit organizations with your computer. I suggest Boinc which uses the idle time on your computer for scientific research.