Here's a pic of my Rocky Mountain Altitude 750 2014. It's the area where the top tube meets the down tube / Bottom bracket.
Is this a cracked frame or just cosmetic problem?
Yep, that looks like some pretty extensive cracking.
I'm sure this is obvious to you, but do not ride this bike as the frame may fail catastrophically.
Sorry your three year old frame failed. I would not expect a full suspension frame to fail in that time. You may want to contact Rocky Mountain to see if they will do anything about it.
On the other hand, kudos to you for being able to ride the bike hard enough that you broke it :-)
Thank you for the confirmation of what I felt was obvious for me!
In fact the problem started from, I broke my swingarm (see pic below). When dismounting the bike and cleaning it for warranty, I inspected the rest of the frame to see if there's any other small cracks, where I saw that. My LBS, is telling me that those are not cracks and they only want to Warrany my swingarm... :(
Oh... and another crack that is "normal" for my LBS! :S