I've gotten a few questions about how to save time making blinkies. One trick that I LOVE and that really speeds things up is the flip feature. This tutorial is good for beginner blinkie makers or users who are new to GIMP.
The best part of a blinkie is the blinking border (why else would we call them blinkies?

) This is a quick tip to help you make your border quickly so that you can focus on cute clip art, fonts, or animations inside. Instead of creating separate layers to use as your blinking border, this tool allows you to duplicate one border and just flip it - you are blinking in a couple clicks instead of the time it takes to make a brand new border.
1. Create a new image in GIMP. You can make it whatever size you want your blinkie to be - I like mine to be 150x50.
2. With your new image created, fill it with whatever color you like. Then create a grid to follow for your blinkies. Click Image -> Configure Grid.
3. I like my borders fast, so I always size my grid to 5 pixels. If you want slower bigger borders, make your grid size larger.
4. Once you have your grid to follow, pick your blinking border color and your brush size, and alternate filling the boxes around the blinkie. I put dark blue over light blue on this blinkie. At this point you will have only ONE layer (see the layers menu on the right hand side.)
5. In the layers menu click the duplicate layers button at the bottom of the menu (it looks like two little screens together.) You will end up with an identical layer. Your layers menu will show 2 layers now.
6. Select the "flip" tool from the Toolbox menu (it looks like a book, open, with a two way arrow over it). Move your cursor over the new layer you have created and click. GIMP will flip your layer right over. You can test this by clicking the eye next to your new layer - if you click on and off the eye your blinkie will blink and show how it will look once it is animated. I also suggest you rename your layers - I like "on" and "off". With names, it's much easier to put in a bunch of duplicated layers once you have your blinking pattern established and still keep them in order.
Now you can carry on with your design!