Browser-Specific Image
Remember how I used an HTML/CSS trick¹ to embed two images in a post, and different people would see a different image depending upon which browser they were using (pretty much either IE, or everybody else). Well, here's a single image which looks different in different browsers:
How does it work? Fucking magnets! It's an APNG (animated PNG) file. The image has two frames; but only Firefox supports the APNG format, so it skips to the second frame and stops there. Neither IE, Chrome, nor Safari, support the APNG format; so they display the first frame only. To embed this in your journal, just use the following code:
tp://pics.livejournal.com/allah_sulu/pic/003zbgqs">
Unfortunately, I don't have a graphics program which supports the creation of APNGs, so I can't make customized versions for my own evil fun. According to somebody on Reddit, the APNG format² is also supported by Opera, Adobe Photoshop, and GIMP.
¹Thanks to LJ's recent code changes, that trick still works in posts but no longer works in comments.
²In case you didn't bother clicking on the above links (tl;dr), the APNG is an unofficial extension to the PNG standard. So there are good reasons why many programs don't support it yet, if it's still subject to revision or rejection.