Support multiple image formats encoded as base64

[brannondorsey]

Right now, runway.data_types.image support serialization via a JPEG encoded image only.

model-sdk/runway/data_types.py

Lines 77 to 84 in b3e2aa7

	def serialize(self, value):
	if type(value) is np.ndarray:
	im_pil = Image.fromarray(value)
	elif type(value) is Image.Image:
	im_pil = value
	buffer = IO()
	im_pil.save(buffer, format='JPEG')
	return 'data:image/jpeg;base64,' + base64.b64encode(buffer.getvalue()).decode('utf8')

We should support multiple image formats, as well as exploring support for higher bit-depth images.