Hello. Is there a recommended image size to use? I tried playing with a picture and the pattern would of needed to be huge to have nice detail. (My apologies, I am not a natural with technology...) Thanks.

The detail of the pattern is limited by the number of stitches. Having a much more detailed image will therefore not result in a more detailed pattern. My recommendation would be to have at least two times as many pixels in width and height as you will have stitches. For example if your resulting pattern will be 500 x 400 stitches (which is already pretty large ) the minimum image size would be 1000 x 800 pixels. For modern camera's that is still a low-resolution image 

Higher resolution images won't hurt though, it will only take a few seconds more in the upload process.