Redmine

I have created ticket using email in my instance of Redmine Application.

Email signature has some png files (like company logo, social networking site logos for my company etc).

In Settings> Incoming Emails : I have added "End of ticket" and "Reply Above this line" so that I could Truncate emails after one of these lines to
exclude anything non relevant to ticket while creating it using email.

Ticket is created truncating email signature but company Logo is still added as an attachment.

These files get added in file system as as /files/2013/10/23/logo.png etc

While deleting this issue it is found that Redmine does not have permissions to delete these attached files and hence deleting this issue gives error page.

I could chmod this file path to +777 and got it working.

Not sure if I am doing anything wrong here? any setting in my server not correct ? or is this really Redmine Bug?