The one big difference is that can now add a cover photo to your profile page on Google Plus similar to Facebook. And if you have applied some clever hacks – like animated GIFs – to your existing profile pages, there’s no reason to worry as you still have an option to stick to the older layout which has five thumbnails in a row.
The recommended dimensions are:
- Profile Picture – 250×250 pixels
- Cover Photo – 940×180 pixels
- Thumbnail Photos – 110×110 pixels
The following video has more details on how you can customize the profile page of your Google Plus account. Also, this slide has more detailed information on the layout and dimensions of profile photos.