trailing #, thumbnail will be centrally cropped, ensuring the requested dimensions.
trailing >, thumbnail will only be modified if it is currently larger requested dimensions. (i.e. the :small thumb for a 120×80 original image will be unchanged)
You can (re)generate your thumbnails en masse with Paperclip’s rake tasks. Using our example class above:
rake paperclip:refresh:thumbnails CLASS=User
or to refresh all of your defined styles in one go (:thumb, :small, :medium from the above example)
rake paperclip:refresh CLASS=User
and to refresh only missing styles:
a list of styles will be defined or updated in a file “/public/system/paperclip_attachments.yml”
If you are using the gem required version of paperclip the rake tasks may not be auto-loaded, but you can copy them into your lib/tasks directory if needed.
If you need more manual control or have a lot of thumbnails and only want to process a few, you can use #reprocess! like so:
users_to_reprocess.each do |user|