Remove and resize Wallpapers

Hi guys...just playing with my new GR-501

Took me a while to figure out the actual screen size for new wallpapers!
Its funny how many sites out there have varying dimensions for this phone! lol

In the end, I finally figured out the 240x400 dimension.

I also learned that when editing a new wallpaper, to keep in mind that the very
bottom area (about 60 pixels) of the image is hidden.
So the actual visible image size is only about 340px vertically.

Anyway...I have a question (and I couldn't find an answer here):
I would like to delete (remove) the wallpapers that are already in the phone memory.
There are 11 images that I don't want to keep*.
And for those, the Trash option is not visible when viewing in the Picture Folder.
I also can't see them on my PC when using the data cable.


*Although two of those are plain black images, that I assume are for the "Black Theme"
and maybe they are required?