For anyone looking to bring their Nexus 3172PQ/TQ non XL switch up to date. 

Compact img files are required as the older N3k only had 2gb of flash storage. 

Install n3100-compact.7.0.3.I7.10.bin first, then go ahead and delete the old NX-OS image.

Once that's done, repeat and install n3100-compact.9.3.15.bin.

File hashes for security purposes are available on Cisco's Software Download center. 
Keep in mind the hashes are for the un-compacted files. 

https://software.cisco.com/download/home/285001669/type/282088129/release/7.0(3)I7(10)

https://software.cisco.com/download/home/285001669/type/282088129/release/9.3(15)