In my application ,I have stored uploaded images to folder ./assets/uploads. I am using easyimage and imagemagick for storing the images.
In my application, after up
Sails uses grunt to handle asset syncing. By default, the grunt-watch task ignores empty folders, but as long as there's at least one file in a folder, it will always sync it. So the quickest solution here, if you're intent on using the default static middleware to server your uploaded files, is to just make sure there's always at least one file in your assets/uploads folder when you do sails lift. As long as that's the case, the uploads folder will always be synced to your .tmp/public folder, and anything that's uploaded to it subsequently will be automatically copied over and available immediately.
Of course, this will cause all of your uploaded files to be copied into .tmp/public every time your lift Sails, which you probably don't want. To solve this, you can use the symlink trick @bredikhin posted in his answer.