Ram Question

I have a macbook6,1 processor 2.26 GHz Intel core 2 duo Memory 2 GB 1067 MHz DDR3 Mac OS X version 10.6.8

I want to add more ram but I would rather have a person install the memory for me. I called the company here that Apple referred me to. I was looking at upgrading to 4 GB but she told me I could go to 8 GB or could put 4 in one and make it 5GB. I have tried to research on here and other sites and see the pros and cons. I get the spinning ball so much. I mostly work with pictures and Photo Shop Elements but have about 2000 images on my computer. (the rest are on an external drive.)
Is the 8 Gb running smooth on these macbooks or presenting problems?