EC2 user permissions

I just set up my first instance of AWS EC2 server and I'm running into an issue with permissions on a script uploading pictures. 'var/www' (and all subdirectories) owner is 'ec2-user' however the apache server is running as 'apache'. Therefore all directories created dynamically by the php script (using mkdir) have 'apache' as the owner (which it seems doesn't have write permissions) I could certainly change the apache user to 'ec2user' but I'm worried that might be a security risk. What's the correct way of doing this? Thanks for your help.