Converting some icons creates black stripes on transparency

[Jacket]

For a project of mine I'm fetching websites favicons and storing them to be displayed in a website. Sounds pretty trivial, but I have one strange issue. Almost all icons come in a .ico format, which is not very web friendly. Some icons also have different sizes in them. I'm using Imagemagick to convert them to PNG and extract only the 16x16 icon.

I'm using the following command line for this:

Code: Select all

convert source.ico -geometry 16x16 -alpha on -background none -flatten out.png

Unfortunately on some icons this creates some nasty horizontal black stripes in the transparent areas. Here is an example:

This is the original icon:

http://g.etfv.co/http://www.mysqlperformanceblog.com/

This is the result:



Here it is again embedded here:



What could be wrong here? My ImageMagick is version 6.5.4-7

[snibgo]

You are using an ancient version of ImageMagic. With v6.8.5, your command gives me no black lines.

[Jacket]

Thanks I will update. This is the version that comes with CentOS 6.4.