Re: Steam crashing when clicking on videos and screenshots
Which Ubuntu version (and is it 32 or 64-bit) are you running and what video card or chip do you have and default or other video drivers? No clue why you would have trouble with images. And not sure if Flash works automatically in 32-bit. Because Steam is 32-bit, for 64-bit Ubuntu I originally had to mkdir ~/.local/share/Steam/ubuntu12_32/plugins and put 32-bit libflashplayer.so in that for Flash to work in Steam. Although, without that Steam did not crash, it just said I was missing a plugin and provided instructions that did not work in Linux.
What desktop are you running (Unity?)? As far as exiting Steam, I always just use Steam > Exit from its own menus at the top (if you were just playing a game sometimes it has to finish syncing with the Steam Cloud).
I have been using Steam in 64-bit Ubuntu 12.04 w/nvidia drivers since late Linux beta in January before it was released, mostly for Team Fortress 2, but I also bought Half-Life and Counterstrike when they were on sale.If you install Steam on another system, your games and stats should automatically be there (after they download). I did that temporarily in Win7 (which never had Steam before) when the far end of my drive with Linux started failing, until I got everything transferred to a new drive.
i5 650 3.2 GHz, 8 GB, nvidia GTX 750 Ti, 32" 1080p | i7-4700MQ, 8 GB, Intel HD 4600/nvidia GTX 765M, 15.6" 1080p | etc.