Am I obliged to use .rec files to read images from S3?


I find this a bit confusing.

Several places across the MXNet documentation read: Any data iterator that can read/write data from a local drive can also read/write data from S3.

Probably I am missing something, but I guess this is true ONLY IF the data has been pre-packaged into a .rec file.

Reading raw JPGs from S3 does not work for me.

In an ideal world I would like to run the following
data_iter ="s3:/my-bucket-containing-jpg-images")
which evidently does not work.

Am I somewhat obliged to turn all my dataset into .rec and .lst before streaming it from S3?
No raw format supported?