Sorry for the late reply, it's been hectic these past weeks.
@ alessandrofrancesconi: Not sure how I can explain better. Essentially when I open the BIMP option under File>Batch Image Manipulation and try to select a directory with .jpg images it won't let me. As in I can't select the directory (folder) or the individual files in it.
@ Ofnuts: Thanks for the links! I'll give them a try and see what happens. I've already made a layer with my watermark, but the thing is I have around 300 images I want to add the watermark to, hence why I'm trying to avoid doing it one-by-one; might die haha.
@ saulgoode: I'm using Mac OSX 10.8. Not sure how that changes things.... =/
Thanks for the reads and answers!!