(Until i've had a chance to post this on the site properly, this will live here)
ContentThe simple rule is "one word".
Your image should contain a single word, or if more than one word is visible, it should clearly be obvious which is the word you're posting.
Our reference is the Oxford English dictionary, in fact, the one I have on my bookcase at home. If it does not appear in the dictionary, it is unlikely to be accepted.
We also may not accept words if they additionally contain unsuitable content (whilst swear words may be accepted, they may be 'rated' for later viewing preferences).
For proper nouns and brand names, currently, we're not accepting them if they don't appear in the dictionary. If a brand name appears in the dictionary under another meaning, it may be accepted.
Our word is final, if for some reason we don't feel the image should be included in the dictionary, we're happy to discuss it, but at the end of the day, if we say no, you should accept our final decision.
TechnicalWe'd love to support more image formats, but currently whilst we're in beta, we're accepting JPEG images (med-high quality please) between 640x480 and 1024x768. Images are automatically scaled to 640x480, so if you're manually scaling them anyway, thats the size to aim for.
Upload via HTTP is always shakey at best. Try and keep your images below 1Mb
Ideally, we like 4:3 ratio images, but we know sometimes they'll be cropped, and it doesn't always turn out like that, so we're flexible on that.