This is a free for homeuser image browser and editor.
I use it daily for all the little edits and with the "edit with external programs" I can send an image to some other program (it also has shortcuts for them).
For the full screen image it has a great way of hiding the options palettes on the sides of the screen.
It can browse RAW images too.
A lot of other useful things to try.
For me it's the default browser.
(try the portable version - it's a ZIP archive, no install, leaves the Registry clean, unpack and run it)
I like the Faststone viewer. I have used it on and off for years.
It updates regularly so the program is always improving and compatible.