Chrome: Imgur is a popular choice for quickly sharing images. Imgur Extension by Metronomik takes a few extra steps out of the process for Chrome users.
Once the extension is installed, you'll see a "rehost image" option when you right-click on any image file in Chrome. You can also click the Imgur icon in your extensions list to open up a new tab where you can drag and drop multiple files from your computer to automatically upload to the service. Once they've uploaded, just mouse over the thumbnails and click "copy link" to get direct URLs for the hosted files. If you have an Imgur account, you can also connect it from this page to enable uploading into specific albums.
Imgur was pretty fast to begin with, but this distills the process to a simple right click or drag and drop, without ever having to visit imgur's site. It's fast enough that it will probably replace Bloodrop as my quick image link generator of choice.