Image errors after updating

I cannot upload any photos unless I chmod 777 the “uploads”, and “month” folder.
Last month folder has chmod 755 and it worked just fine.
When sending photos to editor I only have the “title” and “full size” options, “thumbnail” is gone.
I also have a separate php script installed on the same website but on a different mysql database.
I’m having there too problems with uploading the photos, in fact I can upload them but they will not display.
Strange huh ?
Anyone any ideas ? Maybe something to do with the host ?

Thanks