Generate features using Pretrained Net for Smaller image (e.g. 11*11)

Could you please help in creating features (output at the end of Convolution layers and before MLP) using pre-trained network for smaller images?

I am working with images of 11*11 size and have fairly large dataset of about 300K images.

Following example in following link: http://mxnet.io/tutorials/r/classifyRealImageWithPretrainedModel.html

Problem is here net requires images of size 224*224.