Orange Pi is an alternative of the Raspberry pi form China, but It is very cheap than Raspberry pi. I buyed an Orange Pi PC it technicaly like Raspberry pi 2.
It contains Allwinner H3 1.6 Mhz Quadcore CPUMali 400, 600 Mhz GPU, Samsung DDR3 Ram, 10/100 Network adapter, 3 x USB2, Standart size HDMI, composit headphone out. Orange Pi It also contain IR sensor, OTG port and microphone as different from Raspberry Pi 2.
Orange Pi have many OS choice on own web site but those operating systems are not up to date. My personally suggestion is Armbian that really stable and up to date.
Does Raspberry Pi images work with Orange Pi ?
Off course not. The Orange Pi's processor is totally different than Raspberry Pi.
I use Orange Pi as a Web server. I'm pleased with his performance.