Strange behaviour with Imagemagick’s convert file permission

For some weird reason I haven’t been able to find out why or how to change this, the image conversion on the new server, using Imagemagick’s “convert” command failed to set the right permissions to the output files, I spent a long time searching for some resources on the web about how to change the converted file permission of a converted image by Imagemagick’s convert command but all I got was more or less info about permission preventing the file to be converted.

So at the end I decided to see if inserting a simple system command that chmod the files after conversion would work.

It did.

So the problem is fixed, but I still don’t know why the permission aren’t right to start with, so if anyone’s got an answer feel free to share.