Best neural network for feature extraction from images?

Currently, I am using resnet50 to extract features from an image (image is resized to 224 by 224). I want to know whether this is the best neural network for extracting features or are there others that are even better. At the moment, I am extracting a 20 feature vector from one image and a 6 feature vector from another image (resnet50 used for both of them)