Apologies if this question is in the wrong forum but I'd like to know if it's possible to convert my revenue, or some of it to credits to buy pictures from other photographers? If so, can you point me to the link to do so please.
Yes, it's possible to convert your earnings. Go to your Management area and there is a Convert Earnings section in the Contributors Area (above the Statistics button). Just press this button and you'll be asked to confirm the earnings amount you want to be converted. Good luck with this!