If you really want to make slide show and which should be GIF format and no flash required, no registration required but you can create great GIF animated slide show without using any extra software, like as photoshop and so on. Simply use Gickr‘s free service and create your animated GIF picture within a short time.
Up to 10 photos you can upload and you can fix the showing speed and even you can upload from your pc. If you have flickr account, you can select your tags and user name and setup the size and speed and automatically Gickr will do the rest of work for you. Pixel available with the size of 100, 200, 300, 450. If you need you have the option to manage avatar size