A question about "Test Dataset"

[bit2erswe2t]

Thanks for the amazing job.
When I have been learning the project, I find the "Test Dataset" is 5k images of the "ILSVRC2012_img_val" Dataset in " README.md". As we know, the "ILSVRC2012_img_val" Dataset has 50k images.
Would you please teach me how to select 5k images in 50k images of the "ILSVRC2012_img_val"?
Looking forward to your reply.