Yes, but sometimes 777 is not enough. In the past I use a server who run Confixx. This server set the files writen by server itself to the owner 'wwwrun' and not to my name 'web99'. To find out wich owner is used, to the directorycheck from adminpanel and look which owner got the testfile. Then change all files in Avatars, Attachments and logfiles directory to this owner.
Take care for any file that was generated from the admin panel such as stylesheets and languages files. Check out the ownership and permissions of those files too.
If you run PhotoPost do this for every thumbnail and midsize picture.
Then you'd need to change them to the owner that is writing them - the web user (in your case 'wwwrun') that should allow users to change their avatars. Sometimes things get uploaded as 'nobody' so in certain situations you won't be able to modify files like this after they've been uploaded, if the scripts are running as 'nobody' or another user which doesn't have permission to modify files in your webspace you'll be out of luck.
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