Here you find a quick fix for a wordpress problem i found nowhere written:
I have a wordpress instance running on shared hosting which requires having group read bit set in permissions of uploaded files to be readable by the web server. But uploaded files were set to 0600 instead of 0640 and were thus not viewable on the website.
First i tried setting FS_CHMOD_FILE but this didn’t work as it is not used for uploaded files.
Then i found that wordpress determines the permission bits of uploaded files by taking the permissions of the target directory and if needed the parent directory of it and removing the execution bits. So to solve the problem just set the permissions of wp-content/uploads and all sub directories to 0750. This way wordpress sets file permissions for uploads to 0640 as required.