You mean like a timed transition that occurs with or without user input? I don't think that's possible unless you make the Flickr and embed the slideshow because while you CAN embed flash objects on Insanejournal, you can't use any of the scripting languages that would be required to create a timed slideshow. However, I did find this amazing code for a slideshow that you could put on Scribbld by creating a style, which I can write up a tutorial for if it hasn't been already. Let me check the Scribbld tag on this comm to see.