. Most blinkies are 150x50 plx. The size of my images are 500 x 250 plx and I found this easier to work in and add text. You will be able to play around with the size to fit your side bar when you make the gif at Picasion.
Next go to Picasion and upload your images in the order you want. Then resize them to fit your side bar by clicking custom on the "size" option. I set my size to 220 after playing around a bit. After you have your size and speed you think you want click create animation and a gif. will be generated for you along with a code for you to add a HTML gadget into your side bar or blog post..