To use the Paperclip gem to upload images, you first need to install ImageMagick, which allows Paperclip to manipulate your photos. Then add Paperclip to your gem file and type, "paperclip," and install the bundle. Once Paperclip is installed, you can create a model as usual, and add images as attachments. You also need to add a few fields for Paperclip to run, including Image File Name, Image Content Type, Image File Size and Image Updated At.
Once you set up the database, you have to inform Rails that the model you're working on has a Paperclip attachment. To do this, use the "has_attached_file" process, which specifies a custom path for saving your files.
After following these steps, Paperclip is ready to use. There are many online resources that describe and give detailed examples of the codes you need to input for specific applications of Paperclip. The codes allow you to specify the parameters of a layout or whole album, including the size and ratio of images and the location of image storage. Other codes allow you to specify the parameters of an avatar.
The Paperclip app was developed by Jon Yurek at Thoughtbot in response to a demand for a better method of uploading and managing images in Rails. To find specific codes for Paperclip features, you can browse resources such as RichonRails and SitePoint.