You were on the right track. Pick an annoying and distracting image from a long scene. Hell, I just might borrow the one you used.
After that, just change about one pixel color a time until you get enough images. Keep them small for quite uploading. But I figure you already knew that.
The only secret is to be prepared before hand. Hell, I have over 1000 images to sage with. Also, don't use text. You can post textless posts much quicker than posts with text.