问题
I am just another average joe hoping to jump onto the social network bandwagon. I'd like to know which photo uploading/resizing gem I should use for users of my app. It would be great if you could explain why.
回答1:
Carrierwave has good support for exterior things such as DataMapper, Mongoid, Sequel and even can be used with a 3rd party image managment such as cloudinary The solution seems most complete with support coverage for about anything, but the solution is also much messier (for me at least) since there is a lot more code that you need to handle. It is actively maintained with a plethora of add-ons created by its rich community for support for many features. It also features migration instructions from other attachment solutions such as paperclip. It has about 3-4 active contributors/maintainers
Paperclip is from thoughtbot so it should be a well planned, fully featured, easy-to-handle solution for attaching files. It utilizes many built-in functions that make the experience less straining in a Rail environment. Paperclip is better for an organic Rails environment using activerecord and not all the other alternatives. Paperclip is much easier to handle for beginning rails developers and it also has advanced capabilities for the advanced developer. It has about 2-3 active maintainers. Looking at the github graphs, it seems that last few months haven't been very prolific for paperclip, with relatively few commits to the code. Hope this changes and it can be up to par with carrierwave (usually more maintainers mean more code)
Dragonfly is a rack based attachment solution. It has much support for other frameworks other than Rails, it has several addons for exterior service support but as seen from its github page, a lot is still missing. This is probably due to it having 1 active maintainer and no commit since April 2012. If it doesn't get some real boost, I don't see it living for so much longer. Especially with Rail 4 coming out soon.
At the end of line, each solution has its pros and cons, and each solution works best for each developer.
See the following list with what people has to say about each and decide whether the problems they present concern you:
Rails 3 paperclip vs carrierwave vs dragonfly vs attachment_fu
https://stackoverflow.com/questions/1614842/what-is-the-best-file-upload-attachment-plugin-rails?rq=1
Attachment_fu or Paperclip for Rails3
Carrierwave or Dragonfly
To answer your question - both carrierwave and paperclip can do uploading and resizing of images.
As for you question in the comment, I use paperclip but since carrierwave has a capability to migrate to it from paperclip I might switch if it no longer suits my needs. At the moment it does.
The best way to choose is to pick one, try it, and decide for yourself.
来源：https://stackoverflow.com/questions/14028017/heading-into-2013-should-i-go-with-dragonfly-or-paperclip-or-carrierwave