Most labels generated by Whiplash are in the .zpl format for Zebra printers, meaning you can't see from your file manager what the label looks like.
Shipping Labels can be downloaded as .PNG files from Order Details using the "Download Label" button in the "Print Packing Slip" menu.
Free, web-based ZPL viewers
Tools like Labelary make label viewing trivial, and don't require a login or download. Upload your label to their website: http://labelary.com/viewer.html
You can also open ZPL files in a text editor.