tadpoles just turned to frogs

Hi we have some tadpoles from a small pond where my daughter went to camp. Several now have become full fledged frogs. they're tiny about the size of a pencil eraser. Now that they're frogs we're not sure what to feed them. we have no idea what kind they are. We'd like to release them back into the wild but would prefer to wait until they're not so small.
Any suggestions.
thanks