How to read image data offline without using the browser


I uploaded a lot of images and resized them using RMagick and everything is working fine.

Now I need to resize the existing images to some different dimenstion. In my existing controller all the processing starts after I have

params[:image][:data] in my controller.

My question is how do I get the image data when I am reading the file. Does anyone have an existing code to read an image and get something similar to params[:image][:data] ready for processsing. I knwo how to read an ASCII file but don’t know how to read an image file.