Convert favicon.ico to png to using ImageMagick Procedurally

Question

It looks like ImageMagick does not always convert a single favicon.ico file to a predictable single png file - for some favicon's, it generates a bunch of other favicon-01.png, favicon-02.png, etc... Is there a way to figure out which one's the actual converted favicon you want - or figure out how many got generated, to delete the unwanted ones?

Answer 1

I came across with the same problem while I was trying to convert blogger's favicon and I solved it by using -flatten parameter of Imagemagick like this:

convert "favicon.ico" -thumbnail 16x16 -alpha on -background none -flatten "favicon.png"

Answer 2

This likely happens because there are multiple images in the icon file - this is to provide differet resolutions for different contexts. Presumably you'd want to run a search in the target directory for favicon*.png, then check the dimensions of each one to find the one you wanted (deleting the others as you go).

Answer 3

I guess some of these are animated gifs. You can take the first one as described here:

• http://www.imagemagick.org/script/command-line-processing.php

i.e.:

$magick> convert 'images.gif[0]' image.png

I don't have ImageMagic installed, but you might try the above for all favicon.ico, it might work fine.

Otherwise, you would probably need to write a script to check for favicon-01.png and, if it exists, rename it to favicon.png and delete favicon-*.png (provided you don't have anything else named like that in the working folder).