yup - you can only use images that you created yourself or that you have permission to use.
GerbilGoods posted the link to the answer in the Help section - but if you clicked the Help link, under Contributors Program - the 3rd link says Royalty Payments
Quote:Q: How are Royalties paid to contributors on Zazzle?
A: Monthly Royalty Payments
When unpaid royalties reach $25, Zazzle will send a payment at the end of the following month. You may choose monthly royalty payments to be made via Paypal or mailed check.
For monthly royalty payments, the default (and lowest) payment threshold is $25. You may increase the payment threshold to any amount. When unpaid royalties in any month reach your payment threshold, Zazzle will send a payment at the end of the following month. The modified payment threshold does not affect yearly payments: if your balance on January 31 is above zero, you will be paid according to the yearly royalty payment schedule (above).
Yearly Royalty Payments
If your account does not reach the $25 threshold for monthly payments, you will be paid once yearly as follows:
If unpaid royalties on January 31 of the year total $5 or more, Zazzle will send a payment by the end of February. You may choose your yearly royalty payment to be made via Paypal or mailed check.
If unpaid royalties on January 31 of the year total less than $5, you will only receive a payment by the end of February if you have selected Paypal as your payment option.
Payments on Hold
You may choose to put your royalty payments on hold. You will not receive either monthly or yearly payments while your payments are on hold. Your royalty balance will still be available as a payment method on the Zazzle site.