Image handling in Rails

Image handling in Rails

I want to implement profile images to my Rails app, but I'm not quite sure
what goes in to the whole proces to enable a user to upload and manage her
images. What would be the most efficient way to go about doing this 2013?
I'd prefer to do as much of the heavy-lifting on the client side as possible.
What can I expect from libraries such as jQuery File Upload and Plupload,
can everyting (selecting, uploading, previewing, resisizing/cropping,
storing) be handled with those or do I need heavy backend solutions
(Carrierwave, Paperclick etc) as well?
If some code or libraries would be given as examples of what does what and
where, generally speaking I prefer task-specific libraries rather than
all-in-one solutions.
I'm expecting the users to have modern browsers (FF20+, Chrome20+, IE9+,
Safari5+).