The width of the foot across the top, the widest direction, is 3.5 cm. Her foot is about 8 cm around the widest spot,
7 cm long from heel to toe,
... and about 2.5 cm tall from arch to ankle, here:
The ankle ball photos are because elve seems to have gotten an Idol body with very funky ankle balls.(later note--Impldoll did a batch of ankles with small balls--they need to be either jury-rigged with new balls of you need to get new ones from Impl (send photos, though). The ones on Erzulie, who is one of the first Idols, are just fine. Also here is a goofy diagram of how the strings cross in the pelvis (they are strung like Iplehouse dolls now) :p
By the way, that is a Star Bella there on the Idol body. She had a large head for the Star body.