Google Mail is changed the interface and most of buttons label have been changed from Text to logo. If you are not happy with updated Gmail interface i.e, buttons that changes from text to logo then here is way to revert it back from logo to text. Go to Gmail Settings > General Tab > Button Labels > Select the radio button of text > Save changes. You are done and now you can see all button labels in text instead of icon and if you want icon in the near future then you can change it at any time..