This is a short Instructable aimed at Pocket users who have found the Save to Pocket Firefox extension too slow and don't want to show the whole bookmarks bar in order to display a single link. All you need is the Custom Buttons Firefox extension.
Once you have installed Custom Buttons, the easiest way to create a new button is to right click on the firefox toolbar and choose "Add new button..."
In the image box, paste this base64 code or come up with your own image. Note that the height must be 16px. If it is bigger, it will expand the height of your toolbar to fit the size of the image.
When you click the button, it will work just like the Pocket bookmarklet, but it will have an image and be in your toolbar. If you want to change anything on it, just right click the button and choose "Edit button..."