Your signature breaks the rules because there are too many images:
Here's the rule...
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1. No more than three images are allowed. All of the following each count as an image: (1) A photo, (2) A Clipart, (3) A Countdown, (4) A 'sparkly' signature, (5) Any non DISboard smilie, (6) Eggs. Note also that WISH images each count toward the maximum of three images allowed.
Thus if you have a sparkly signature line, 2 photos, 3 countdowns, 2 eggs, and 1 WISH, your total image count is 9, or triple the allowed number.
Remember, if you add any type of Holiday decorations to your signature, it all counts toward 3-image maximum.
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Unfortunately, if you turned your four photos of your kids into one photo, then that one photo would be too big (if they were the same size.).
Your filesize might also be too big, you might want to add them all up.
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3. The TOTAL filespace of all your images combined must not exceed 50KB. (That's 51,200 bytes).
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Other than that! Cute kids!