The browser is usually an OS default, so I'll mention the multi-select keys for windows (macs use the command key in place of ctrl but that's about the main difference). To select multiple files, hold the control key, and click each file individually, or alternately you can hold shift and click to select everything in between the first selected file and the last one you choose.
After selecting the textures you'd like to use in the browser, the upload should work as planned
hopefully this solves any confusion
Last edited by Rekd; Oct 5, 2014 at 03:32 AM.
Reason: oop, fixed a mistake