How to crop an image into small sections automatically in R

Hello all,
I'd like to crop an image into 15 sections in R. The image projection is Geog lat/long, extending 87 to 120 degree in East and 45 to 55 degree in North. I want to separate it by every 2 degree. So I have 17 degree in X coordinate and 5 degree in Y coordinate. 17 x 5= 85 sections. And then every section has own names such as crop1, 2, 3 etc. Can I do this automatically in R?
Thank a lot